primary aluminum hpdc alloys for structural casts in...

Primary aluminum HPDC Alloys for Structural Casts

in Vehicle ConstructionRHEINFELDEN ALLOYS

Table of contents RHEINFELDEN ALLOYS – Ductile HPDC Aluminum Alloys for Automotive Structural Applications

General

Alloys

Technical information

RHEINFELDEN ALLOYS GmbH & Co. KG

Customer support and R & D

Aluminum casting alloys

Silafont ®-38 (Sf-38) – AlSi9MnMgZn

Castasil ®-37 (Ci-37) – AlSi9MnMoZr

Castasil ®-21 (Ci-21) – AlSi9SrE

Magsimal ®-59 ( Ma-59) – AlMg5Si2Mn

Magsimal ®-plus (Ma-plus) – AlMg6Si2MnZr Castaduct ®-42 (Cc-42) – AlMg4Fe2

Profile of the alloys for the die-casters

Technical Informations / Processing datasheets

Technical informations

Disclaimer and imprint

2

3

4 – 5

6 – 11

12 – 13

14 – 17

18 – 19

20 – 25

26 – 35

36 – 37

38 – 44

45 – 52

52

1

RHEINFELDEN ALLOYS GmbH & Co. KG

“Progress by tradition”

ALUMINIUM RHEINFELDEN Group: This history of aluminum

in Germany started at Rheinfelden. In 1898 Europe’s first

river power station brought about the establishment of the first

aluminum smelter in Germany, at Rheinfelden, Baden.

The company has always operated in three business segments

and in October 2008 restructuring turned ALUMINIUM

RHEINFELDEN GmbH into a holding company and independent

GmbH & Co. KGs.

www.alurheinfelden.com

Our policy

RHEINFELDEN ALLOYS GmbH & Co. KG: Our innovative

character is what allows us to adapt rapidly to fast changing mar-

ket needs. The agility of a private family owned operated company,

the central geographic location in the European casting metal

market, the know-how and experience of our team, are factors

making a difference for customers looking for reliable tradition and

modern innovation. Efficient and effective use of casting aluminum

is on the forefront of our new developments in materials.

It is RHEINFELDEN ALLOYS philosophy to fulfill requested

standards of quality, either ISO/IATF or VDA. Please ask for our

actual certificates or have a look at our homepage.

Products of RHEINFELDEN ALLOYS can be found wherever

steel designs or iron casts can be replaced by light aluminum

casts. RHEINFELDEN ALLOYS is a powerful partner, especially

to the automotive and mechanical engineering sectors in provid-

ing alloys designed to the process and cast part based on the

customer’s particular needs. We also offer papers like this hand-

book about favorable alloys for designers of structural die-casts.

www.rheinfelden-alloys.eu · Tel. +49 7623 93 490

We offer customized alloys and new solutions for high perfor-

mance materials and light weight components with focus on

low carbon foot print products. In this mood we developed new

high strength die-casting alloys and an innovative alloy family for

structural casts in the automotive industry.

Please have a look to our alloy selecting tool:

www.rheinfelden-alloys.eu/alloytoy

Panoramic view of the entire RHEINFELDEN ALLOYS complex

RHEINFELDEN-Ingot

2

R & D and Customer Support

When RHEINFELDEN ALLOYS develop new materials we always aim to achieve efficient and

specific use of aluminum casts. Through the use of materials, tailored and refined to increase

performance, RHEINFELDEN ALLOYS is constantly striving to help reduce vehicle weight

and therefore cut emissions. We run development projects with the goal to optimise the mech-

anical and casting properties of our aluminum HPDC alloys. Our recent developed alloys are

Silafont-38, Magsimal-plus and Castaduct-42.

RHEINFELDEN Customer Support and RHEINFELDEN TechCenter

Every product and every customer has individual requirements of the material. The Customer

Support Team at RHEINFELDEN ALLOYS has the job of anticipating these needs and producing

tailored materials, fitting the casts and your requirements. Please contact our Customer Support

Team and use our TechCenter installations at RHEINFELDEN ALLOYS also for your foundry

concerns. We can advise on the use and design of casts and the choice of alloy. Use our experience

for your success as RHEINFELDEN ALLOYS customer.

RHEINFELDEN alloys globally

Our development of special HPDC alloys results to patents for Castasil-21, Castasil-37,

Magsimal-59, Magsimal-plus and pending patents in 2017 for Castaduct-42 and Silafont-38.

Our license partners produce these alloys globally, especially DUBAL in Dubai, NIKKEI NMA

in North America and also in China.

In this cooperation all here described alloys are available globally. Please ask for a possibility of

local production by our partners.

3

Alloys for Structural Casts by RHEINFELDEN ALLOYS

Structural components

Casted structural components are mostly large, but always stability

defining parts. They fulfill the idea of lightweight by dimensional

stability and functional integration. In the case of a crash high energy

absorption is recommended.

Dimensional stability is during the production process positively influenced by

• Easy castability

• Suitable die-cast design

• High strength achieved without heat treatment

RHEINFELDEN ALLOYS, as alloy producer support the use of

casted structural components and developed several HPDC

alloys for that purpose. Silafont-36, Castaman-35 as AlSi10MnMg

alloys are established since years. This handbook summarizes

the new alloys for structural casts.

Quick finder for selecting the right alloy

The following table provides an overview of RHEINFELDEN

ALLOYS’ new alloys. The existing alloys are described in

former handbooks in detail. The new alloys were developed

for structural, cases and chassis components as well as

for battery, electric motor and high-voltage applications in

the field of E-mobility.

excellent

very good

good

all right

poor

— not applicable

AlloyChemical denomination S

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Silafont-38 AlSi9MnMgZn – –

Castasil-37 AlSi9MnMoZr – – –

Castasil-21 AlSi9SrE – –

Magsimal-59 AlMg5Si2Mn – – –

Magsimal-plus AlMg6Si2MnZr – –

Castaduct-42 AlMg4Fe2 – – –

HPDC ALLOYS FOR

STRUCTURAL APPLICATIONS

• Silafont-36, AlSi10MnMg

• Silafont-38

• Castasil-37

• Magsimal-59

• Magsimal-plus

• Castaduct-42

4

An alloy, produced for large HPDC structural parts in the automotive industry. In the meantime

several OEMs recognized the advantages of these alloys for car structural or electrical

applications: high dimensional stability, can be used without heat treatment, shape well and

easy to weld, or by Castasil-21 with highest electrical or thermal conductivity.

Nature’s equivalent: the vine shoot which turns towards the sun, flexible, elastic and yet

incredibly tough and strong. > page 12 – 17

Castasil ® – large surface, high dimensional stability, fantastic to cast

A family of materials which can be adapted to the part specifications and to the customer’s

individual production process with ultimate precision. Can be easily processed, outstanding flow

properties, is modified with strontium to further enhance properties. Silafont is for complex,

delicate components which have to satisfy precisely defined requirements and, if they feature

the right components, make maximum production efficiency possible. Silafont emulates flowing

water that flows around every stone and fills every cavity. > page 6 – 11

Silafont ® – an infinite wealth of properties

An alloy family for delicate parts which need to retain their strength and precise form

over a long period. Good weldability, high resilience, can be used in virtually any application.

Supreme corrosion resistance, even to salt water.

Parts which simulate the structure of the wings of a dragonfly: wafer thin, elastic and yet

offering incredible strength and resilience, they enable this dainty insect to fly distances that

never cease to amaze. > page 18 – 25

Magsimal ® – of filigree lightness, but extremely resilient

An innovative HPDC alloy family also for large-area components like structural casts in

thin-walled design. Modern lightweight construction is easy to realize thanks to excellent cast-

ability, use in the as-cast state and a smart alloy composition with its low specific weight,

even for higher temperature applications in battery housings of the E-cars.

The temperature-loving Emerald lizard produces the same fascination with her long flexible

body > page 26 – 35

Castaduct ® – Always fascinating pliable down to the finest detail

5

Silafont®-38 (Sf-38) An infinite wealth of properties

The HPDC alloy Silafont-38 was developed by RHEIN-

FELDEN ALLOYS to further increase yield strength

compared to Silafont-36 without significant change in

ductility.

Several hardening elements are alloyed in defined ranges in

the Silafont-38. That’s the cause why the advantage is with

a T6 heat treatment. The first step – solutionizing – is still

necessary, but the cooling may differ.

Even with an air quenching to lower distortion the complex

alloyed Silafont-38 reaches 180 MPa yield strength after

artificial aging.

Besides these moderate cooling rates it is possible to

cool down with water after the solutionizing treatment

to achive highest strength.

Additionally Silafont-38 has also following properties re-

quired for the pressure die-casting process:

• excellent castability even with varying wall thicknesses

• no sticking to the mold; the low-iron Silafont-38 is there-

fore alloyed with manganese and strontium

• excellent machinability

In more and more applications, mainly in car manufacturing,

other properties of Silafont-38 are of increasing importance:

• good corrosion resistance due to specially balanced

composition

• high fatigue strength and crash performance due to

reduced effect of disturbing Fe and Si phases

• excellent weldability for aluminum profile – cast designs

• suitable for self-piercing riveting

KEY FIGURES of Silafont-38

• no sticking to the mold; the low-iron Silafont-38 is therefore

multi element alloyed

• very high YTS in conjunction with T6 including air quenching

• good corrosion resistance due to specially balanced composition

• excellent weldability for wrought aluminum profile – cast designs


Example of use

6

Areas of use

Light-weight car body structures for vehicles, gearboxes, battery housings mechanical engineering.

Chemical composition of Silafont-38 in the ingot [ % of mass ]

Mechanical properties

Physical data

Silafont ®- 38 [ AlSi9MnMgZn ]

Casting method

Treatment state

Quenching cooling

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

HPDC F 135 – 160 270 – 300 4 – 8

HPDC T6 Water 230 – 280 300 – 350 6 – 9

HPDC T6 Air 180 – 210 250 – 290 8 – 11

[ %] Si Fe Cu Mn Mg Zn Ti Zr others

min. 8.5 0.1 0.4 0.3 0.1 0.1

max. 10.0 0.15 0.4 0.8 0.4 0.3 0.15 0.3 Mo; Sr

Density [ kg/dm3 ]

Coefficient of thermal expansion [ 1/K × 10-6]

Thermal Conductivity [W/(K × cm)]

ElectricalConductivity [ % IACS ]

Shrinkage [ % ]

2.69 21 1.5 36.0 – 41.5 0.4 – 0.6

KEY FIGURES of Silafont-38

• Further development of the well-known Silafont-36 for the use in ultra-high strength

and crash-relevant structural parts in the automotive industry.

• Complex alloyed Primary Aluminum HPDC alloy with low Fe content.

Also a Strontium permanent modification for very high elongation with good ductility.

• Low distortion T6 heat treatments with cooling in moving air could be realized

(Cooling rate after solution treatment: at least 3 °C/s down to 200 °C).

• Excellent dynamic fatigue strength.

• Very suitable for applications in vehicle designs.

Heat treatable to high elongation and high energy absorption capability.

• Replaces steel sheet constructions in vehicle designs.

• Allows weight reductions of up to 40 % compared to die-

casting standard alloys in the field of vehicle structural parts.

• Excellent machinable and very good suitable for all

welding processes.

• Very suitable for riveting with applicable riveting processes

and tools.

• Very good corrosion resistance:

Coatings may be unnecessary.

• Excellent castable HPDC alloy: Solidification range,

shrinkage behavior and expected mold endurance

are comparable to that of AlSi9 and AlSi10Mg alloys.

• Best mold release: No sticking to the mold.

• Excellent castable for casts with wall thickness above 1.5 mm.

7

100 µm 100 µm

Silafont ®- 38 [ AlSi9MnMgZn ] – Properties

Tab. 1: Chemical composition of Silafont-38, AlSi9MnMgZn in the ingot (in mass-%)


min. 8.5 0.1 0.4 0.3 0.1 0.1

max. 10.0 0.15 0.4 0.8 0.4 0.3 0.15 0.3 Mo; Sr

Fig. 1b: Microstructure of Silafont-38, AlSi9MnMgZn, in the T6 stateFig. 1a: Microstructure of Silafont-38, AlSi9MnMgZn, in the as-cast state, 3 mm sample plate

Requirements for lightweight construction with the aim of higher

strength for thin-walled designs in structural casts are constantly

increasing. The potential of Silafont-36, the structural alloy

known worldwide as the standard, continues to be exploited,

especially by optimizing the die-casting and heat treatment

processes. RHEINFELDEN ALLOYS has achieved a further in-

crease through an alloy engineering development in conjunction

with a low-distortion heat treatment method with the Silafont-38

described here.

Alloy description

In the development of the alloy Silafont-38, particular atten-

tion was paid to the castability (Tab. 1). Generally, castability is

comparable to a Silafont-36. The wider solidification interval due

to the higher concentration of copper and zinc even increases the

mold filling capacity. A further reduction of the silicon would in-

crease the elongation, but then reduces the very good flowability.

The sticking tendency is reduced primarily by the high manga-

nese content, but also by iron and strontium. In this AlSi alloy, the

Mn content crystallizes in hexagonal Al6Mn intermetallic phases;

a crystal form that allows high deformations of the cast, since

there are no serious sharp edges in the microstructure of the

casting alloy. Several casting tests confirmed the good castability

of the Silafont-38.

The increase in strength through a T6 heat treatment is achieved

primarily by intermetallic phases with magnesium, copper and

to a lesser extent also by zinc. Magnesium in an alloy range of

0.28 to 0.35 % allows a good increase in T6 strength, even if this

process is performed as a low-distortion variant in the air stream.

Molybdenum is dissolved in the α-crystal of aluminum and forms

no detectable by light microscopy phases. Nevertheless, this al-

loying increases strength starting from a content of 0.10 %.

In contrast, zircon has a content of 0.10 % as a strength-enhanc-

ing grain refiner.

The set in close tolerances levels of magnesium and copper give

in this ratio a good corrosion resistance, since so the formation

of corrosion-promoting intermetallic phases is not promoted. Al-

though higher levels of Cu would lead to an increase in the yield

strength, but worsen the corrosion behavior.

Modification

The modification of the AlSi eutectic is achieved by the addition

of strontium (Sr) and favors a very fine, coral-shaped solidification

of the silicon in the eutectic. This refinement is achieved in die-

casts of Silafont-38 with a Sr content above 80 ppm.

Above a level of 350 ppm Sr, the general tendency of the melt

to oxidize increases, which would lead to an increased hydrogen

content of the melt. This should be considered in structural casts

for welded assemblies, as this is also a cause of weld porosity.

Metallurgically, only a Sr content above 450 ppm leads to the

formation of coarser, moreover Mg-containing mixed crystals, that

is to say for over-refinement. A reduction in elongation can then

be seen as well.

8

0

100

200

300

400

500

600

0 50 100 150 200 250

Tem

pera

ture

[°C

]

Time [s]

Air flow

Water HISAQ

Air

Mg2SiQ_Prime

β"β_Prime

B_Prime

100 °C/min 10 °C/min


Fig. 3: Cooling curves with different cooling agents at 3 mm HPDC platesFig. 2: Calculated phase diagram for the time temperature curves of the different MgSi precipitations in Silafont-38

Metallography and phase simulation

In Fig. 1a, metallographic microstructures from the die-casted

alloy are shown in 500-times magnification. In condition F, a very

fine eutectic can be seen, which allows a very high deformability

already in the as-cast state. Intermetallic phases are under

10 microns in size, thus very small and evenly distributed.

The solidification of Silafont-38 starts with the Al6Mn-containing

phase at about 600 °C. Essential for the alloy, however, is the

formation of the modified Al-Si eutectic at 550 °C. A fine distribu-

tion of the AlMnFeSi phase is necessary for a high ductility and

is typically maintained in the die-cast structure with an Mn

content of between 0.4 and 0.8 %. The intermetallic Zr phases

also influence a fine structure of the Silafont-38.

For strength, submicroscopic precipitates in the Al solid solution

are essential. Such precipitates can be calculated using a phase

simulation. Fig. 2 shows the metastable MgSi phases, which

decisively influence the strength. For their shape, the initial state

of the material produced by the casting process, the solution

annealing and the quenching condition is important. If they have

a suitable size, they lead to high strength of the casting material.

Heat treatment

In the TechCenter Rheinfelden die-casted plates of dimension

200 × 60 mm are poured and T6 heat treated (Fig. 1b). An ad-

justment of the material characteristics achievable on 3 mm test

plates with large-area structural casts took place. The mold filling

of these panels resembles that of high-quality cast large struc-

tural casts more than might be expected. A significant difference

is the quench rate after removal from the mold or after the heat

treatment. Small plates can quench significantly faster, which

has an effect on material properties. The achievable strengths,

especially at the yield strength, increase considerably. For this

reason, a heat treatment installation has been built up which ap-

proximates the quenching conditions of an industrial production.

The quench rate was set at 3 °C/s for this laboratory method.

Fig. 3 shows temperature curves of 3 mm plates at different

quenching conditions. Clearly, the rapid temperature cooling

when immersed in water can be seen. After removal from the

oven, the onset of cooling only delayed by 8 seconds. The

different measuring curves when cooling with air are also due

to the different intensity of the air flow. In terms of metallurgy,

it is important to cool down to around 200 °C, below which the

cooling may then proceed more slowly.

With this determination, material characteristics such as Tab. 2

and Fig. 4 could be measured on test plates in the TechCenter.

These are comparable to those from typical industrial production

processes.

Silafont-38 can also be cooled down after solution annealing

with a considerably faster air cooling, as well as with the special

water-polymer cooling Aluquench®. The material characteristic

values are shown as the mean value of about 50 samples each

in Tab. 3. The respective increase of the yield strength from the

solution annealed state follows the higher cooling rates of these

processes.

Typically, with faster cooling, the distortion increases due to

higher residual stresses. Only the water-polymer cooling of the

Silafont-38 achieves maximum strength without significant

distortion. With water cooling, there is always a higher distortion

of the structural cast geometry.

9

Silafont ®- 38 [ AlSi9MnMgZn ] – Properties

Casting Method Treatmentstate

Quenching cooling

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

HPDC F 138 299 8.4

HPDC T6 Air 3 °C/s 192 264 10.5

HPDC T6 Air > 10 °C/s 209 288 11.0

HPDC T6 Aluquench 257 332 10.0

HPDC T6 Water 272 344 6.0

Tab. 3: Mechanical properties of Silafont 38, AlSi9MnMgZn in the T6 state and with different cooling agents

350

300

250

200

150

100

50

00 2 4 6 8 10 12

Elongation E [ %]

Str

ess

R [

MP

a ]

T 6 Air

F

T 6Water

Temper T6 Air

YTS = 185 MPa

UTS = 278 MPa

E = 10 %

Temper T6 Water

YTS = 272 MPa

UTS = 344 MPa

E = 6 %

Temper F

YTS = 147 MPa

UTS = 290 MPa

E = 5.5 %

Fig. 4: Stress-strain curve for Silafont-38, AlSi9MnMgZr, as-cast state and T6 cooled with air or water

Casting Method Treatmentstate

Quenching cooling

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

HPDC F 138 299 8.4

Standard deviation 3 8 0.8

HPDC T5 Water 220 317 6.2


HPDC T6 Air 3 °C/s 192 264 10.5


Tab. 2: Mechanical properties of Silafont-38, AlSi9MnMgZr plates in comparison F to T5 water cooled and T6 air cooled; the standard deviation is calculated of 50 casts

10


This shows the importance of the high alloy content in the

Silafont-38 in order to achieve the requirements of mechanical

properties with minimal component distortion.

Short-term and long-term stability

Aging of the casts is tested by testing at 205 °C for 1 hour and

at 150 °C for 1000 hours. Thereafter, the mechanical proper-

ties of the components made of Silafont-38 must not have fallen

below the specifications of mechanical strength.

Silafont-38 has passed this after heat treatment with the air

quenching used here at 3 °C/s after solution annealing.

Rivetability

The strength of a material affects the rivetability. Materials

with higher strengths must be joined with other rivets than

materials with low strengths. For this reason, the rivet geometry

and parameters of the die-casting alloy Silafont-38 have been

adjusted. The high deformability of the Silafont-38 led to crack-

free riveted joints.

Weldability

In addition to high material parameters, good weldability is re-

quired for structural casts.

To check the weldability, a production-accompanying, manually

executed welding test can be carried out. Such a test result with

Silafont-38 is shown in Fig. 5 compared to the standard Sila-

font-36 alloy. Both results are far beyond the requirements.

Corrosion resistance

A salt spray test (ISO 9227) and an intercrystalline corrosion test

(ASTM G110-92) were performed at external laboratories. The

corrosion behavior of 3 mm sheets of Silafont-38 in this case was

compared with that of Castasil-37, AlSi9MnMoZr.

The corrosion-influencing difference to this alloy is in the higher

levels of Cu and Zn, as well as Mg in the Silafont-38.

The evaluation after 336 hours of spray test revealed a similar

corrosion resistance of the two alloys. One difference was in the

nature of the corrosion attack. Castasil-37 as a high-purity alloy

tended to pitting corrosion, while the zinc and copper fractions

of Silafont-38 were more likely to cause areal corrosion.

Case study

A HPDC test was also carried out on the structural casts as in

Fig. 6, which is installed as a door frame reinforcement of a

convertible. It is characterized by high strength requirements for

the crash-relevant components with a wall thickness of up to

2.1 mm. The aim was to top yield strength of 180 N/mm² with at

least 8 % elongation.

This sophisticated component has been previously die-casted

in series in the alloy Silafont-36 with Mg 0.35 % with a T6 heat

treatment with water quenching after solution annealing.

With unchanged pouring parameters, Silafont-38 was changed

to a T6 heat treatment with air-shower quenching after solution

heat treatment.

With the help of a vacuum-assisted casting technology, the struc-

tural casts (Fig. 6) was casted in a “double cavity” mold. The char-

acteristic values from Tab. 2 were achieved in the as-cast condition.

Further, the T5 condition was achieved by quenching in water after

casting. Cooling after solution heat treatment at T6 was performed

by an air shower at 3 °C/sec. These are averages of about 50

tensile bar samples; the standard deviations is also given.

Fig. 5: Welding beam on tested structural part, Silafont-36 (left) and Silafont-38 (right) Fig. 6: Door frame reinforcement, Silafont-38 T6 Air quenched

11

Castasil®-37 (Ci-37)Large areas, high dimensional stability, fantastic to cast

Development by RHEINFELDEN ALLOYS Castasil-37

shows good mechanical properties, especially elongation,

which are superior to those of conventional AlSi-type

alloys. Out-standing castability and weldability enable the

casting of complex designs. Self-piercing riveting trials

in the as-cast state led for example to good results.

The properties are mainly influenced by alloying with silicon,

manganese, molybdenum and strontium. A low magnesium

content is essential for the excellent stability of long-term

stability of mechanical properties.

Specially chosen chemical composition enables the

following casting properties:

• excellent castability

• suitable for minimum wall thicknesses

• no sticking to the mold

With increasing number of applications, mainly in car

manufacturing, other properties of Castasil-37 became

also important:

• high fatigue strength

• very good corrosion resistance

• excellent weldability



• suitable for adhesive bonding applications

KEY FIGURES of Ci-37

• suitable for different wall thicknesses

• highest fatigue strength compared to AlSi-alloys


• no aging, best dimensional stability in as-cast


Example of use

12

Castasil ®- 37 [ AlSi9MnMoZr ]

Wall thickness [ mm ]

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

2 – 3 120 – 150 260 – 300 10 – 14

3 – 5 100 – 130 230 – 280 10 – 14

5 – 7 80 – 110 200 – 250 10 – 14

Density [ kg/dm3 ]




Shrinkage [ % ]

2.69 22 1.4 31.0 – 38.0 0.4 – 0.6

[ %] Si Fe Cu Mn Mg Zn Mo Zr Ti Sr others

min. 8.5 0.35 0.1 0.1 0.006

max. 10.5 0.15 0.05 0.6 0.06 0.07 0.3 0.3 0.15 0.025 0.10

Areas of use

Connection nodes for space frame designs; thin-walled body parts; architecture, cars, lighting, aircraft, domestic appliances,

air conditioning, automotive engineering, foodstuffs industry, mechanical engineering, shipbuilding, defence engineering;

replaces high pressure die-casts with T7 or T6 with air quenching.

Distinguishing characteristics

HPDC alloy with excellent castability. Very high elongation in as-cast state as a result of which it can be used in more ways

when in as-cast state. Further increase in ductility thanks to single-stage heat treatment. No distortion or blisters from solution

heat treatment, very good corrosion resistance, no long-term ageing due to heat, good machinability, ideal for riveting and

adhesive bonding in automotive engineering.

Chemical composition of Castasil-37 in the ingot [ % of mass]


Physical data

Stress-strain curve for Castasil-37, AlSi9MnMoZr, in the as-cast state (F)

Elongation E [ %]

Str

ess

R [

MP

a]

Temper F

YTS = 125 MPa

UTS = 277 MPa

E = 14.9 %

F

Wöhler’s diagram for Castasil-37, AlSi9MnMoZr, in the as-cast state (F)

Str

ess

R [

MP

a]

Number of load cycles [n]

95 %

5 %

106 107 108105

50 %

200

180

160

140

120

100

80

60

40

20

0

Wöhler's diagram for Castasil-37Stress ratio r = -14 mm wall thickness, form factor K t = 1.2 5 %, 50 %, 95 % fracture probability

104

13

Castasil-21 is a HPDC alloy developed by RHEINFELDEN

ALLOYS for casts with outstanding requirements in terms

of electrical or thermal conductivity.

Aluminum 99.7E for rotors has indeed higher electrical

conductivity, but in praxis you need lower contraction for

huge casts, like with an alloy with more than 8 % silicon.

The application of Castasil-21 may help to lower the weight

of HPDC, especially for the light weight design of cars

with their additional casts like battery housing, conductor

plate for electronics, LED-lighting, but also for general

purposes of heating and cooling.

Chemical composition was optimized in order to have high

conductivity (up to 30 %) compared with usual HPDC

aluminum alloys and still around 10 % higher than with

Silafont-36.

The specially chosen chemical composition results in


• excellent casting ability with good ejectability

• well usable for thin wall fins

More and more applications either in car design or in

telecommunication area need also following properties:

• very good corrosion resistance to weather

• good mechanical strength compared to Al for rotors


• flangeable or deformable to fix parts together


• electrical conductivity comes up to 48.5 % IACS,

to substitute Cu in the idea of light weight design or

Al 99.7E in rotors

Castasil®-21 (Ci-21)Large areas, high dimensional stability, fantastic to cast

KEY FIGURES of Castasil-21

• well usable for thin wall fins

• very good corrosion resistance to weathering

• good mechanical strength; excellent machinability

• electrical conductivity comes up to 48.5 % IACS,

to substitute Cu in the idea of light weight design

or Al 99.7E in rotors

Example of use

14

Castasil ®- 21 [ AlSi9SrE ]

Temper YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

Brinell hardness[ HBW ]

F 85 – 100 200 – 230 6 – 9 55 – 70

O 80 – 100 170 – 200 9 – 15 55 – 65

[ %] Si Fe Cu Mn Mg Zn Ti Sr others

min. 8.0 0.5 0.01

max. 9.0 0.7 0.02 0.01 0.03 0.07 0.01 0.03 0.10

Areas of use

Also for all kind of casts with requirements in terms of high thermal or electrical conductivity. Conductor plate for electronics,

automotive and mechanical engineering, LED-lighting, air cooling, electronic boxes or covers, E-mobil applications, inclusive

electric engines.

Chemical composition of Castasil-21 in the ingot [ % of mass]


Physical data

Density [ kg/dm3 ]




Shrinkage [ % ]

2.69 22 1.9 43.0 – 48.5 0.4 – 0.6

• Very good values for the elongation at state O: Elongation

up to 15 %.

• Excellent machinable and very suitable for welding processes.

• Suitable for crimping processes.

• Excellent castable HPDC alloy. Solidification range,

shrinkage behavior and expected die-casting mold endurance

are comparable to that of AlSi9 and AlSi10Mg alloys.

• Existing die-casting cells for AlSi alloys must not be modified.

• Well suited for casts with minimum wall thickness (from

1.5 mm).

• Very low heat cracking tendency and very good release

properties.

KEY FIGURES of Castasil-21

• Very good electrical conductivity: 25 to 28 MS/m (43.0 to 48.5 % IACS) in the state O

• Very good thermal conductivity: 1.6 to in the state O 1.9 W/K × cm

Annealing of casts for the state O leads to the highest conductivities compared to other AlSi HPDC alloys.

• Very good corrosion resistance to water and weather. Coatings are often not necessary.

15

Castasil ®- 21 [ AlSi9SrE ] – Properties

Chemical composition

Table 1 shows the Castasil-21 composition with a silicon content

of 8 to 9 %. Thus, the processing temperature is 680 – 750 °C,

an area with typical thermal shock wear of casting chamber and

cavity. Strontium causes a further lowering of the eutectic point,

that is the melting temperature, of about 6 – 8 °C. In die-casting

alloys Strontium reduces the affinity of the melt to the mold, i.e.

the tendency to stick on, although Castasil-21 is already alloyed

with an Fe content from 0.5 to 0.7 %.

As an impurity in this conductive alloy are magnesium and zinc

contents of more than 0.08 % and a copper content more than

0.02 %. While forming the conductivity disturbing solid solution

phases these elements are already at lower levels, but this is

negligible compared to the effects from the die-casting process

(Fig. 1). Not so with the manganese and titanium content.

Here a value of only 0.01 % should not be exceeded in order to

keep the conductivity high. Because Castasil-21 is produced

with primary aluminum as base, further accompanying elements

are also kept very low.

Electrical conductivity

But more important is the modification of the silicon crystal during

solidification. The strontium addition causes a coralline

solidification structure of the Si crystal in the eutectic, the so

called modification. The relevant Castasil-21 advantage of this

modification is the higher conductivity of plus 2 – 4 MS /m.

Heat treatment

The processing in the die-casting is characterized by a very rapid

solidification. Although this achieves higher strength and hard-

ness, this microstructure is negative for achieving high conductiv-

ity ! Casts out of Castasil-21 can even further be increased

in their conductivity by one-stage heat treatment, whereby

the internal stress of the cast structure is equalized then. In the

as-cast state a die-cast with 6 mm wall thickness may reach

even 25 MS/m.

A heat treatment of 350 °C for 2 h or 250 °C for 3 h provides

superior conductivity of around 28 MS/m (Fig. 2). In this state,

the die-casts have 83 % of the conductivity of Al 99.7E. Upon

the cooling of the components after the stress-relieving may

only slowly air cooling to be made.

Handling instructions

Cleaning and processing the melt should result in a low achieved

oxide impurity. A strontium content of 100 to 350 ppm ensures

the modification. Ingate design and die-cast parameters must be

optimized to result in a solid structure without pores, due to these

technically disturb the conductivity. Please look for handling

instructions for details of melt preparation.

Ele

ctric

al c

ondu

ctiv

ity [

MS

/m ]

353433323130292827262524232221201918171615

AlSi12(Fe) 170 °C 250 °C 350 °C Al for rotors

1h 2 h 3 hFF F 1h 2 h 3 h 1h 2 h 3 h

Castasil-21

Con

duct

ivity

[MS

/m]

Content of alloying element [ %]

35

30

25

20

15

10

Cr Mn

ZrTi

Cu

FeZn

Si

0 0.2 0.4 0.6 0.8 1.0 1.2 1.4

37

Tab. 1: Chemical composition of Castasil-21, AlSi9SrE in the ingot (in mass-%)

Fig. 1: Relationship between electrical conductivity of Al99.9 and added alloying elements

Fig. 2: Electrical conductivity of Castasil-21 through heat treatment of the HPDC

Mg

[ %] Si Fe Cu Mn Mg Zn Ti Sr others

min. 8.0 0.5 0.01

max. 9.0 0.7 0.02 0.01 0.03 0.07 0.01 0.03 0.10

16


Heatsink for electronic deviceCastasil-21; temper O170 × 70 × 70 mm; weight: 0.4 kg

This cast with fixed electrical divice has to diffuse the hot spot of heat through the massive plate and the casted fins and should lower the maximum temperature ever.

Higher heat conductivity of the alloy results directly in lower temperature. It is not necessary to design longer fins or add forced air ventilation.

Heatsink for electronics boxCastasil-21; temper 0460 × 160 × 65 mm; weight: 1.5 kg

Heat conducting housing for switching electronics in carsCastasil-21; temper 0160 × 200 × 55 mm; weight: 0.57 kg

17

Magsimal® -59 (Ma-59)Of filigree lightness, but extremely resilient

Magsimal-59 developed by RHEINFELDEN ALLOYS

is a widely used HPDC alloy for automotive applications.

This alloy type has excellent properties in the as-cast state,

i.e. high yield strength in conjunction with high ductility.

High energy absorption capacity, e.g. in the event of a crash.

The fatigue strength is also higher than for conventional

pressure die-cast alloys.

Most applications are therefore safety components with

high performance requirements e.g. safety-belt pretensioners,

steering wheel frames, crossbeams, motorbike wheel rims,

control arm, suspension-strut brackets and other flap or

chassis components.

The properties of Magsimal-59 depend on the wall thickness

and on cooling method after HPDC. A one step heat treat-

ment is suggested to compensate these differences and to

result in up to 30 % higher YTS. Air quenching would be the

best, due it excludes distortions and results in high rigidity.

The alloy Magsimal-59 is produced on a primary metal

basis and therefore manifests high analytical purity.

This produces as a consequence outstanding mechanical

strength and an excellent corrosion behavior.

Specially chosen chemical composition enables the


• very good castability

• suitable for minimum wall thicknesses

• low sticking to the mold

• excellent properties in the as-cast state

With increasing number of applications, mainly in car

manufacturing, other properties of Magsimal-59 became

also important:

• high yield strength in conjunction with high ductility

• very high energy absorption capacity

• excellent suitable for adhesive bonding applications

• very high fatigue strength

• excellent corrosion behavior


KEY FIGURES of Magsimal-59

• high yield strength in conjunction with high ductility


• excellent fatigue strength even with sea water contact


Example of use

18

Magsimal ®- 59 [ AlMg5Si2Mn ]

Areas of use

Architecture, cars, aircraft, domestic appliances, air conditioning, automotive engineering, foodstuffs industry,

mechanical engineering, optics and furniture, shipbuilding, chemical industry.

Distinguishing characteristics

HPDC alloy with excellent mechanical and dynamic properties with thin walls.

Very good weldability, suited to self-piercing riveting. Excellent corrosion resistance, excellent mechanical polishability

and good machinability, ideal adhesive bonding in car body design.

Chemical composition of Magsimal-59 in the ingot [ % of mass]


Physical data

Wall thickness [ mm ]

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

< 2 > 220 > 300 10 – 15

2 – 4 160 – 220 310 – 340 11 – 22

4 – 6 140 – 170 250 – 320 9 – 14

6 – 12 120 – 145 220 – 260 8 – 12

[ %] Si Fe Cu Mn Mg Zn Ti Be others

min. 1.8 0.5 5.0

max. 2.6 0.2 0.03 0.8 6.0 0.07 0.20 0.004 0.2

Density [ kg/dm3 ]




Shrinkage [ % ]

2.63 24 1.1 24.0 – 27.5 0.6 – 1.1

Stress-strain curve for Magsimal-59, AlMg5Si2Mn, in the as-cast state. Wall thickness of samples: 3 mm

Elongation E [ %]

320

240

160

80

00 5 10 15 20

Str

ess

R [

MP

a]

Wöhler’s curve for Magsimal-59, AlMg5Si2Mn, in the as-cast state

105 106 107 108

200

180

160

140

120

100

80

60

40

20

0

Number of load cycles [n]

Str

ess

R [

MP

a]

Stress ratio r = -1Wall thickness 4 mm5 %, 50 %, 95 % fracture probability

95 %50 %

5 %

Temper FYTS = 178 MPaUTS = 313 MPaE = 20.6 %

19

Magsimal® - plus (Ma-plus)Of filigree lightness, but extremely resilient

The Magsimal-plus, AlMg6Si2MnZr with an additional yield

tensile strength on top to the previous Magsimal-59 was

developed in the RHEINFELDEN ALLOYS TechCenter.

Our aim is to get 10 % more YTS, which means 20 MPa

more and may result in less wall thickness respective less

weight of the cast. Compared to AlSi10MnMg this may be

even 40 % advantage in strength. With this strength even

steel sheet parts maybe substituted with a die-cast and its

advantages for high functional integral design, ready in the

as-cast state.

Despite the high Mg content of Magsimal-plus extraordinary

good corrosion behavior is recognized in our tests.

The properties of Magsimal-plus depend on the wall thick-

ness and on cooling method after HPDC. Air quenching

would be the best, due it excludes distortions and results

in high rigidity.

Magsimal-plus is the ultrahigh-strength AlMg die-casting

alloy for high-tech lightweight construction in the vehicle

structure.

• application in as-cast state for die-casts of 2 – 6 mm

wall thickness

• natural hard alloy with hardening effect

• excellent corrosion resistance against salt water

KEY FIGURES of Magsimal-plus

• excellent yield strength in conjunction

with high ductility

• no further aging effects after short term

T5 treatment, e.g. paint bake cycle after

powder coating



• well suitable for self-piercing riveting

• very high dynamic fatigue strengt

Example of use

20

Magsimal ®- plus [ AlMg6Si2MnZr ]

Areas of use

Architecture, automotive or trucks, aircraft, domestic appliances, air conditioning, automotive engineering,

mechanical engineering, shipbuilding, chemical industry, substitution of complex steel sheet designs or forgings

Chemical composition of Magsimal-plus in the ingot [ % of mass]

Mechanical properties with 3 mm wall thickness

Physical data


min. 2.1 0.5 6.0 0.1

max. 2.6 0.15 0.05 0.8 6.4 0.07 0.05 0.3 Mo; Be

Density [ kg/dm3 ]




Shrinkage [ % ]

2.64 24 1.1 22.0 – 27.5 0.6 – 1.1

Treatment state

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

F 200 – 220 340 – 360 9 – 12

T5 230 – 250 350 – 380 8 – 12

KEY FIGURES of Magsimal-plus

• Magsimal-plus is an AlMgSi high pressure die-casting alloy with excellent mechanical properties

in the stabilized as-cast state for structural parts in the BIW of vehicles.

• The high strength of Magsimal-plus enables very thin lightweight designs. A weight reduction

up to 40 % in comparison to an AlSi10MnMg design may be achieved.

• No T6 or T7 heat treatment required: Cost cutting is possible due weight reduction of the cast and

due skipping heat treatment and straightening after heat treatment’s distortion.

• Excellent corrosion behavior.

• Advanced application range for casts in the as-cast state F.

• Very suitable for applications in vehicle designs: Excellent

energy absorption capacity in the event of a vehicle

crash or impact to battery trays and covers.

• Substitution of complex steel sheet designs in vehicle

designs is possible.

• Substitution of aluminum forgings in vehicle designs is possible.

• Excellent weldable, welding technique should be similar to

5000-series.

• Well suitable for self-piercing riveting, clinched joints and

adhesive bonds.

• Very high resistance to stress corrosion cracking.

Keep in mind:

• The casting of Magsimal-plus requires special know-how

in the field of mold design, melting and casting technique.

21


min. 2.1 0.5 6.0 0.1

max. 2.6 0.15 0.05 0.8 6.4 0.07 0.05 0.3 Mo; Be

Tab. 1: Chemical composition of Magsimal-plus, AlMg6Si2MnZr in the ingot (in mass-%)

Magsimal ®- plus [ AlMg6Si2MnZr ] – Properties

Chemical composition

Table 1 shows the chemical composition of an ingot for the

complex alloyed Magsimal-plus, AlMg6Si2MnZr. At the die-cast,

the Fe, Cu and Zn contents mentioned here as further elements

may be slightly higher.

With this development, RHEINFELDEN ALLOYS offers an

AlMgSi die-cast alloy with particularly high mechanical strength

combined with high elongation, achievable even in as-cast con-

dition. The Zr and Mo contents serve this purpose as well, which

increase the strengthening in the as-cast state by precipitation

hardening to SiZr and Al12(Mn,Mo), shown in Fig 1.

The magnesium-silicon ratio ensures good castability and good

feeding during solidification. The eutectic fraction in the micro-

structure is about 40 %, which is sufficient for processing into

complex casts. Magnesium is present in a deliberately high sur-

plus, based on the compound Mg2Si. This is important because

it must be ensured that there is no free silicon in the structure,

which has negative influence to corrosion behavior.

Furthermore, the targeted high-alloyed magnesium content en-

sures the high yield strength.

The abundant calcium and sodium found in melting flux must be

kept low, as these elements generally negatively affect casting

behavior and, in particular, increase the tendency of hot cracking.

The phosphorus used to inert graphite must also be kept as low

as possible, because this element has a particularly negative

effect on the formation of the Al-Mg2Si eutectic and thus ad-

versely affects the ductility.

Alloy melts of Al-Mg types with magnesium content above 2 %

are tend to increased dross formation when the melt is hold in

the furnace for a long time and the melt temperature is particu-

larly high. Therefore, oxidation-inhibiting alloying ingredients

are added to the Magsimal-plus in the range of few 0.001 %

by weight. This causes the oxide skin to become denser and to

oxidize less magnesium at the melting bath surface.

The thermal analysis of the Magsimal-plus is shown in Fig. 2. The

temperature curve was recorded with a Quick-Cup sand crucible.

The liquidus temperature is about 615 °C and the solidus tem-

perature is about 590 °C. Here the Al-Mg2Si eutectic solidifies.

Fig. 3: Microstructure of Magsimal-plus, AlMg6Si2MnZr; 3 mm plates; magnification 1000x

Fig. 2: Thermal analysis of Magsimal-59, AlMg5Si2Mn, in a Quick-Cup-Crucible

0 2.5 5.0

640

630

620

610

600

590

580

570

560

550

540

Time [min]

Tem

pera

ture

[°C

]

[°C]

TG = 670.0TLu = 611.3TLo = 615.1dTL = 3.8TSu = 592.6TSo = 593.0dTS = 0.4

Fig. 1: Calculated phase diagram for main precipitations during solidification of Magsimal-plus, AlMg6Si2MnZr

22

Fig. 4: Stress-strain curve for Magsimal-plus, AlMg6Si2MnZr in the as-cast state (F) and temper T5

Tab 2: Average mechanical properties of Magsimal-plus, AlMg6Si2MnZr in the as-cast state and after T5 from test plates and typical HPDC parts

Elongation E [ %]

Str

ess

R [

MP

a]

0 3 6 9 12

400

350

300

250

200

150

100

50

0

F

T5

Temper T5with 3 mm plateYTS = 229 MPaUTS = 359 MPaE = 10.1 %

Temper Fwith 3 mm plateYTS = 206 MPaUTS = 342 MPaE = 10.9 %


The microstructure of the HPDC as shown in Fig: 3 is character-

ized by a uniform distribution of the Al6Mn phase. Manganese

prevents sticking in the die-casting mold. Around the α-dendrites,

the eutectic is distributed between α-aluminum and Mg2Si.

There are no coarse phases in the overview and the eutectic is

very fine and spherical; therefore, this is a very ductile structure.

Mechanical properties in the as-cast state

For Magsimal-plus, AlMg6Si2MnZr a characteristic material

property is found in the quasi-static testing of AlMg alloys. The

tensile test shows small spikes in the stress-strain curve. These

are not cracks in the material, but it is the so-called strain aging.

This phenomenon occurs in the plastic range of the stress-

strain curve. It is an interaction between dissolved atoms and

migratory dislocations in the microstructure (Portevin-Chatellier

effect), which leads to a very short-term and small stress drop

in the stress-strain curve. Fig. 4 shows a typical example of such

behavior.

The mechanical properties of the Magsimal-plus also depend on

the wall thickness respectively on the solidification conditions.

Table 2 shows the mechanical properties in the as-cast state and

after T5 heat treatment. The mechanical properties shown were

determined on vacuum assisted sample plates and samples of

structural die-casts with a wall thickness of 3.0 mm.

In addition, the aging at room temperature has to be considered,

which occurs in thin-walled, natural hardening Magsimal-plus die-

casts after demolding and water-quenching.

Only after 20 days or after T5 treatment is the yield strength at

a stable, higher level. For water-quenched casts, the strength

increases by about 30 MPa, but with the use of air quenching

by only 5 MPa higher. However, the elongation at break barely

decreases.

It must be noted that the values in the real cast may vary de-

pending on the proportion of pre-solidification and oxide contents

as well as the flow and solidification behavior during cavity

filling and are generally better in well-flowed cast cross-sections

than in areas of cavity filling end. By connecting overflows and

vents at correct positions this influence can be reduced. There-

fore, the determination of suitable positions for the removal of

test specimens from die-casts is demanding and must be defined

in any case exactly between the foundry and the die-cast part

designer.

Casting Method Wallthickness

Numbers of test pieces

Treatmentstate

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]

TechCenter 3 mm 40 F 208 348 10.4

Standard deviation 2.8 6.5 1.4

TechCenter 3 mm 40 T5 231 363 10.0


Testpart 3 mm 36 T5 239 366 10.2


23

100 µm 2,049 mm

0,603 mm

1,008 mm

0,744 mm

1,773 mm

Mechanical properties after T5 treatment

A further increase in strength can be achieved by a T5 treatment

of the cast at only 200 °C in 30 – 60 minutes. It has been indi-

cated that the cast must be quenched immediately after demold-

ing from the die-casting mold, so that the appropriate increase in

strength during artificial ageing can be achieved. Only a cooling

in air after demolding does not achieve the full effect.

The increase in mechanical properties compared to the as-

cast state is shown in Fig. 4. These mechanical properties were

determined on 3.0 mm sample plates as well as on large-sized

structural die-casts, designed and manufactured to suit the alloy

features.

This short T5 artificial aging treatment thus significantly shortens

the otherwise waiting for natural aging.

In the automotive industry also demands on the short and long

term stability of the mechanical properties are made. Such aging

tests at 205 °C for 1 h or 150 °C for 1000 h, the casts from Magsi-

mal-plus has been successfully passed after short T5 treatment.

Weldability

All-aluminum constructions with structural cast application are

virtually impossible without welded joints. Therefore, butt welds

and fillet welds were tested with die-casted sample plates in the

MIG process, shown in Fig 5a. The Magsimal-plus die-cast sample

plate with 3.0 mm thickness was butt-welded to AlMgSi0.5.

The welding filler material used was an S - AlMg4.5Mn welding wire

with Ø 1.2 mm.

The MIG pulse synergic welding machine TPS-400i from Fronius was

used with a pulsed arc process with controlled material transition.

Thus, the workpiece surface is preheated and achieved an

accurately metered current pulse for the targeted detachment

of a welding material drop. This Cold-Metal-Transfer principle

guarantees very low-spatter welding. The particular advantage

of this connection welding is also the only slight distortion in

particularly thin-walled produced Magsimal-plus die-casts. Both,

outer appearance and inner weld quality were achieved with very

good results (Fig. 5b).

Another subordinate factor is that the Magsimal-plus, unlike

classic AlSiMg alloys, has virtually no hysteresis in the linear

expansion when heated to 300 °C. It is therefore barely expected

component distortion after such heat in the environment of

the weld.


AlMg alloys are usually very resistant to corrosion and are there-

fore also used in a seawater-containing atmosphere.

Since this type of alloy can also be used for structural casts in

vehicle construction, a test for determining the tendency to stress

corrosion cracking is inevitable.

Corrosion resistance was tested with an intercrystalline corrosion

test according to ASTM G110-92 and a salt mist spray test ac-

cording to EN ISO 9227 and was passed with very good results.

Magsimal ®- plus [ AlMg6Si2MnZr ] – Properties

Fig. 5b: Micrograph from the welding beam section between Magsimal-plus and AlMgSi0.5 sheet

Fig. 5a: Cross-section of a butt-welded cast-sheet-connection

Fig. 6b: Cross-section of the punch rivet with some calculations

Fig. 6a: Overview about the punch rivet tests with Magsimal-plus, AlMg6Si2MnZr

24

Riveting capability

In body construction with its various materials, the connection

technology punch riveting plays a major role (Fig. 6a). In this

process semi-hollow punch rivets pierce the overhead steel or

aluminum sheet and dig into the cast (Fig. 6b).

The casting material must be able to withstand the deformations

on the closing head of the riveting mold. A further evaluation

is carried out at closely side by side placed rivets or with rivets

placed close to the cast’ edge in the demand for crack-free clos-

ing heads on the casted surface.

The rivet mold significantly influences the riveting result. The

semi-hollow punch riveting processes have to be optimized for

high-strength Magsimal-plus applications. Sections of the

cast intended for punch riveting should not be designed thinner

than 3 mm to have the required ductility.

Surface finishing

Magsimal-plus can be painted, powder-coated, polished or anod-

ized. Polishing results into a typical slight blue coloration of the

surface gloss. When anodizing, it should be noted that a gray

shade should be formed because of the low silicon content. For

decorative purposes, it is therefore advisable to use a chrome

layer or the polished surface.

Melting process

Magsimal-plus has a special long-term grain refinement particu-

larly affecting the Al-Mg2Si eutectic. The degree of fineness of

the eutectic determines the elongation respectively the tough-

ness of the cast (Fig. 7a). Special alloying elements in alloy

production greatly reduce the oxidation of the melt, which is par-

ticularly characteristic to AlMg alloys. Agglomerations of oxides

on bath surfaces and on the bottom of the furnace are barely

formed. After rapid melting of the ingots a melt cleaning with a

gas rotor have to be carried out. The properties of Magsimal-plus

are retained if no sodium-containing treatment fluxes, no grain

refining and modification agents, no phosphorus, alkali and earth

alkali containing substances and no different metals are supplied

to the melt. Because of this, the Al-Mg2Si eutectic is strongly

influenced and coarsened (Fig. 7b).

The temperature during Magsimal-plus melting should not per-

manently exceed 780 °C. The holding temperature after melting

should be set to 760 °C.

In melting furnaces, which keep the melt moving with heat con-

vection, the form of lids are reduced by less oxide-melt reactions

and segregations. This also applies to furnaces in which the bath

movement takes place by means of rotor or with purge gas initia-

tion by furnace bottom stones. Furnaces with roof heating and no

bath movement cause difficulties for longer holding time. Melting

of all aluminum alloys and also Magsimal-plus reacts less with the

refractory material, if it contains more than 85 % aluminum oxide.

The remelting of runners, return scrap and others is not a prob-

lem. However, care must be taken that mixing with other alloys

cannot take place. This would negatively affect the mechanical

properties.

When using return material, a good melt cleaning by means of

rotor and argon or nitrogen gas is absolutely necessary, since

oxide inclusions, oxide skins, etc. have to be removed. These can

accumulate in the melting and casting process and exert a nega-

tive influence both on the cast properties and on the achievable

mechanical characteristics.

The resulting dross after cleaning and degassing cycle can be

reduced in their metal content with use of sodium-free dross

treatment flux.

Casting process

For further information, please refer to the information on the

processing of AlMg casting alloys in the die-casting process in

the Chapters on Castaduct-42 alloy and design guidelines for

casts and die-casting molds.


Fig. 7a: Fine Al-Mg2Si-eutectic of Magsimal-plus, AlMg6Si2MnZr Fig. 7b: Coarse Al-Mg2Si-eutectic

25

Castaduct®- 42 (Cc-42)Always fascinating pliable down to the finest detail

The Castaduct-42 from the AlFeMg alloy family, newly

developed in the RHEINFELDEN ALLOYS TechCenter,

amazes both the foundry industry and the automotive indus-

try: Highest elongation in the as-cast and non-heat treated

condition, along with a yield strength just achieved with well-

known AlSi10MnMg cast alloys with a T7 two-stage heat

treatment.

The good castability in the die-casting process enables

the production of large and thin-walled structural cast

components. Castaduct-42 can be combined with other

materials in many ways using a variety of established joining

techniques.

Castaduct-42 is plain and robust in its alloy composition,

based on the two alloy components Fe and Mg. The

carefully co-ordinated alloy components of Castaduct-42

enable an easy handling in the die-casting process.

Any melt addition is completely eliminated.

The high Fe content in the Castaduct-42 ensures reduced

sticking tendency and improved die-casting mold life.

The Castaduct-42 is a natural-hard alloy and exhibits excel-

lent long-term stability in the as-cast state, even at high

application temperatures.

The corrosion resistance of Castaduct-42 is excellent.

Further protection and di-electric strength may come with

anodizing.

Next to the applications for structural cast components,

thus the ductile Castaduct-42 also is very suitable for gen-

eral use in the e-mobility: battery cases and trays, cases

and covers for electronic components of the high-voltage

technology.

KEY FIGURES of Castaduct-42

• very suitable for lightweight construction

• highest ductility in the as-cast state

• excellent corrosion resistance

• very well suited for established connection

techniques in vehicle construction

Example of use

26

KEY FIGURES of Castaduct-42

• Castaduct-42 is an easy to handle alloy for BIW parts like structure casts.

• Innovative and plain alloy composition.

Developed on base of AlFe-eutectic composition.

• No T5, T6 or T7 heat treatment required:

Cost cutting is possible due skipping heat treatment and straightening of distortion.

• Excellent resistance to sea water atmosphere.

Areas of use

Large and thin-walled structural casts; connection nodes for space frame designs; battery housings, electronic covers

or shelter housings; thin-walled body parts; for architecture, cars, lighting, aircraft, domestic appliances, air conditioning,

automotive engineering, foodstuffs industry, mechanical engineering, shipbuilding, defense engineering.

Replaces typical AlSi10MnMg high pressure die-casts with O/T4/T7 treatment, but also Magnesium-based HPDC.

Chemical composition of Castaduct-42 in the ingot [ % of mass]


Physical data

• Excellent suitable for BIW automotive structural appli-

cations with requirements of medium strength, but highest

deformability.

• High percentages of in-house scrap can easily be remelted.

• Easy melt preparing without any modifying or grain

structure treatment.

• Very low sticking behavior in the mold, due the high

Fe-content.

• Easy castability in HPDC process, moderate casting tem-

perature, low tendency for pre-solidifications and hot cracks.

• High resistance against high temperature ageing, up to

350 °C no influence to the mechanical strength at RT.

• Well suitable for self-piercing rivets, clinched joints and

crimping. High values of deforming in a bending test are

constantly measured. Much better than with AlSi10MnMg in

the as-cast state.

• Well weldable, with welding technique similar to 5000-series.

• Very well suitable for anodizing, due to the low Silicon

content a bright surface image may be achieved.

• Well suitable for adhesive bonds.

Keep in mind:

• The casting of Castaduct-42 requires special know-how

in the field of mold design, melting and casting technique.

Castaduct® - 42 [ AlMg4Fe2 ]

[ %] Si Fe Cu Mn Mg Zn Ti others

min. 1.5 4.0

max. 0.2 1.7 0.2 0.15 4.6 0.3 0.2 Be

Treatment state

Wall thickness[mm ]

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]


F 2 – 4 120 – 150 240 – 280 10– 22 65 – 75

Density [ kg/dm3 ]




Shrinkage [ % ]

2.69 25 1.4 26.0 – 29.5 0.5 – 0.9

27

100 µm 20 µm

Castaduct® - 42 [ AlMg4Fe2 ] – Properties

[ %] Si Fe Cu Mn Mg Zn Ti others

min. 1.5 4.0

max. 0.2 1.7 0.2 0.15 4.6 0.3 0.2 Be

Tab. 1: Chemical composition of Castaduct-42, AlMg4Fe2 in the ingot (in mass-%)

Chemical Composition

The Castaduct-42 high pressure die-casting alloy is simple and

robust in its alloy composition, based on the Al-Fe-Mg eutectic

in hypereutectic composition of the two alloying components

Fe and Mg. Iron is present in a necessary high content of about

1.6 %. The magnesium content is about 4.3 %.

For Castaduct-42, the Mg content should not fall below 4.0 %

and should not exceed 4.6 %. This is easy to handle at the

melting and casting plant because the Mg content need not be

precisely controlled and not set to tolerances of less than 0.05 %

by weight.

Also, a modification of the eutectic phases is omitted in this type

of alloy. The elimination of silicon as an alloying element elimi-

nates any Mg2Si precipitation hardening, i.e. the Castaduct-42

is naturally hard and has an excellent long-term stability even at

higher temperatures.

Influence of Iron

Fig. 2 shows the calculated constitutional diagram of Casta-

duct-42, AlMg4Fe2 with an given Mg content of 4.5 %. The Mg

is dissolved under HPDC conditions in the primary solidifying

Al-phase. Al solidifies in dendritic shape.

The liquidus temperature in this Al-Fe-Mg eutectic is lowered to

629 °C, the solidus temperature is 580 °C.

The micrographs in Fig. 1a and 1b show the finely formed Al-Fe

eutectic. The overview shows the large proportion of the eutectic.

This ratio of eutectic to α-Al dendrites and the low processing

temperature lead to the good casting properties.

The Fe content of the casts in Castaduct-42 should be kept

between 1.3 % and 1.7 %. Thus, the hypereutectic alloy system is

formed with the precipitation of Al13Fe4. Higher levels lead

to the formation of large and plate-like Fe-containing phases also

under pressure casting conditions, which reduce the elongation.

This also occurs at slower solidification rates, comparable to sand

casting process.

A heat treatment leads to no change in the phases and can

therefore be omitted.

The tendency of Castaduct-42 to adhere to the mold is substan-

tially reduced by the Fe content compared to low-Fe structural

casting alloys. In practice, the dissolution behavior of steel in the

Castaduct-42 melt was halved in immersion tests.

Higher mold endurance is expected and long flow paths can be

achieved with small wall thicknesses.

Disturbing elements of the in Castaduct-42 alloy

However, the fine structure of the Al-Fe eutectic can only be

maintained if the Si content is kept below 0.2 %. Even slightly

higher Si contents form notch-active AlSiFe phases, which result

in a reduction in elongation.

Also Mn contents should remain low alloyed to avoid coarse and

unfavorable solid solution phase precipitations.

Calcium and sodium worsen castability and cause increased hot

cracking tendency and reduced elongation at break. Therefore,

melting fluxes should be used specifically for AlMg alloys.

Fig. 1a: Microstructure of Castaduct-42, AlMg4Fe2 in the as-cast state, 3 mm sample plate

Fig. 1b: Magnification of the Al-Fe-eutectic in the microstructure of Castaduct-42, AlMg4Fe2

28

Fig. 3: Stress-strain curve of Castaduct-42, AlMg4Fe2 determined from 3.0 mm flat tensile specimen

Fig. 2: Constitutional diagram of Castaduct-42, AlMg4Fe2 with 4.5 % Mg

Elongation E [ %]

Str

ess

R [

MP

a]

F

0 4 8 12 16

280

240

200

160

120

80

40

0

Temper Fwith 3 mm plateYTS = 126 MPaUTS = 260 MPaE = 15.2 %


Influence of Magnesium

The Mg content determines the strength of Castaduct-42. The

Mg content increases the strength in as-cast condition by 60

MPa compared to the binary AlFe alloy. The Mg is always dis-

solved in α-Al-phase, but may be present in slightly different

concentrations.

A more Mg leads to higher yield strength, but also to a smaller

elongation. A balance of mechanical properties is achieved at

4.2 % to 4.5 %.

A possible increase in the sensitivity for stress corrosion cracking

is only present above 5 % Mg content. On the other hand, a suffi-

ciently high Mg content should allow the hypereutectic character

and thus the good casting capability.

Alloy melts of Al-Mg types with magnesium content above 2 %

are tend to increased dross formation when the melt is hold in

the furnace for a long time and the melt temperature is particu-

larly high. Therefore, the Castaduct-42 oxidation-inhibiting alloy-

ing ingredients are added in the range of few 0.001 % by weight.

This causes the oxide skin to become denser and to oxidize less

magnesium at the melting bath surface.


The Castaduct-42 stress-strain diagram in Fig. 3 clearly illus-

trates the potential of this casting alloy. With favorable casting

conditions, i.e. a die-casting process tailored to this type of alloy,

even better yield strength characteristics can be achieved in

conjunction with an elongation of up to 22 %.

For Castaduct-42 a characteristic material property is found in

the mechanical testing of AlMg alloys. The tensile test shows

small spikes in the stress-strain curve. These are not cracks in

the material, but it is the so-called strain aging. This phenom-

enon occurs in the plastic range of the stress-strain curve. This

Portevin-Chatellier effect is an interaction between dissolved

atoms and migratory dislocations in the microstructure, which

leads to a short-term and small stress drop in the stress-strain

curve. Fig. 3 shows a typical example of such behavior.

Influence of wall thickness

In the area of common die-cast wall thicknesses from 2 to 4 mm,

the Castaduct-42 shows only minor variations in the mechanical

characteristics.

Tab. 2 shows the mechanical properties in the as-cast state F.

The mechanical properties shown were determined on vacuum

supported HPDC sample plates with 2.0 mm wall thickness.

As part of testing Castaduct-42 with real structure casts, yield

tensile strengths of between 120 and 150 MPa, ultimate tensile

strengths of between 240 and 280 MPa and elongations at

break of 10 to 22 % were measured on tensile specimens with a

wall thickness of 2–4 mm.

It must be noted that the values in the real cast may vary depend-

ing on the proportion of pre-solidification and oxide contents as

well as the flow and solidification behavior during cavity filling

and are generally better in well-flowed cast cross-sections than

in areas of cavity filling end. By connecting overflows and vents

at correct positions this influence can be reduced. Therefore, the

determination of suitable positions for the removal of test speci-

mens from die-casts is demanding and must be defined in any

case exactly between the foundry and the die-cast part designer.

Iron [ % of mass ]

Tem

pera

ture

[°C

]

0 1 1,6 2 3 4 5

800

700

600

500

400

300

200Al13Fe4 + Al13Mg2 + Al

Al13Fe4 + Al + Liquid

1,31 % Fe / 629 °C Eutectic Point

Al13Fe4 + Liquid

Liquidwith 4,5 % Mg

Al13Fe4 + Al

Al + Liquid

29

1,574 mm

0,837 mm 0,398 mm 0,311 mm

1,841 mm


Deformation capability

The Castaduct-42 alloy has a very high deformability in as-cast

condition and is thus also well suited for crash-relevant applica-

tions in vehicle design. The evidence was provided in the context

of alloy development by means of plate bending test for metallic

materials, according to VDA 238 – 100 (Fig. 4) and with Erichsen

cupping tests and confirmed several times by samples of real

casts. Plate bending angles of up to 60 ° are achieved. Bending

angles of more than 70 ° could be achieved with proper casting

conditions. These high measurement values indicate a very good

behavior in punch riveting and similar joining methods.

The Erichsen cupping test is another test for the suitability of a

casting alloy for structural components in vehicle design. Here,

a sheet-like test strip from the cast is deliberately deformed to a

point of first fissure by a ball lowering in the measurement setup.

With increasing sample plate thickness the Erichsen depression

decreases. For a 2.0 mm sample plate in AlSi alloy deformation

values around 3 mm are common. For the same sample plate in

Castaduct-42 the values of 4.5 mm are very high and indicate a

high deformation capacity in the event of a crash.

In the context of alloy development, a hudge amount of punching

tests were carried out with very good results on 3.0 mm sample

plates and on samples of real Castaduct-42 casts (Fig. 5a/5b).

Castaduct-42 was always tested in as-cast condition and showed

very good results.

Welding performance

In addition to the very good punch riveting ability, a good degree

of welding suitability is of great importance for the use of Casta-

duct-42 in vehicle design.

In the MIG process, Castaduct-42 die-cast sample plates 3.0 mm

were butt-welded and fillet-welded to AW-AlMgSi0.5 to test the

weldability (Fig. 6a/6b). The welding filler material used was an

S - AlMg4.5Mn welding wire with Ø 1.2 mm.

The micrographs of the welded seams show a low-pore and finely

structured microstructure, which results in homogeneous material

properties in the joining zone. The silicon free welding conditions

leads here to no significant changes in the mechanical character-

istics. The right choice of welding filler material leads to crack-

free and ductile welds.

For welded joints on aluminum sheets of the 6000 series, i.e.

AlMgSi alloys, the alloy S - AlMg4.5Mn is also recommended as

the welding filler material.

Distance [mm]

Forc

e [N

]

Fig. 4: Load-extension diagram of plate bending test Castaduct-42 , AlMg4Fe2 Fig. 5b: Crossection with calculation of the HSN rivet test in Castaduct-42, AlMg4Fe2

Fig. 5a: Rivet tests connecting steel sheet to HPDC in Castaduct-42, AlMg4Fe2

0 2 4 6 8

4000

3500

3000

2500

2000

1500

1000

500

0

Bending testwith 2 mm platefollowing VDA 238 – 100distance = 6.86 mmAngle α = 56.7 °

Tab 2: Mechanical properties of Castaduct-42, AlMg4Fe2 in the as-cast state; the typical wall thickness of the several tested HPDC are 2–4 mm

Treatment state

Wall thickness[mm ]

YTSRp0.2 [MPa ]

UTSRm [ MPa ]

ElongationE [ % ]


F 2 – 4 120 – 150 240 – 280 10– 22 65 – 75

30



Corrosion resistance was tested with an intercrystalline corro-

sion test according to ASTM G110-92 and a salt mist spray test

according to EN ISO 9227.

In the intercrystalline corrosion test, the samples are aged for

two hours at room temperature in a hydrochloric acid test solution

with 1000 ml H2O, 20 g NaCl and 100 ml HCl 25 %. For the salt

mist spray test, the samples were exposed to a defined salt mist

load for 14 days.

The corrosion resistance of the alloys Silafont-36, AlSi10MnMg

and Castasil-37, AlSi10MnMoZr is generally considered to be

well-suited for structural cast applications in vehicle design.

The corrosion resistance of the Castaduct-42 alloy can be esti-

mated as very well-suited for automotive applications.

Thermal conductivity

The thermal conductivity of Castaduct-42 was measured on

die-casted sample plates in the as-cast state F with a thickness

of 2.0 mm. The samples were heated in 50 °C increments at

10 °C /min from 20 °C to 500 °C and back again. The conductivity

measurement was carried out after a holding time of 60 min each

increment (Fig. 7).

The Castaduct-42 shows itself here with a averaged value of

140 W/(m × K) clearly unaffected by the heat input. A heat treat-

ment would thus lead to any changes in the thermal conductivity

and is primarily due to the absence of silicon.

Heat treatment

The Castaduct-42 is a naturally hard die-casting alloy and does

not require any heat treatments, since no hardening structural

components are present. Stabilization annealing is not required.

Even an annealing temperature up to 350 °C results in no influ-

ence on the cast structure or the mechanical properties after

cooling.

Short-term stability / Long-term stability

Castaduct-42 has excellent aging resistance and excellent di-

mensional stability, which is due to the Si-free alloy composition.

Both the tests of the short-term stability with 1h / 205 °C and

the tests of long-term stability with 1000 h / 150 °C have been

repeatedly successfully passed.

Fig. 6a: Cross-section of a welded cast-sheet-connection in Castaduct-42, AlMg4Fe2

Fig. 6b: Overview from the welding beam section between Castaduct-42, AlMg4Fe2 and AW-AlMgSi0.5; filler material S - AlMg4.5Mn

Fig. 7: Determination of the thermal conductivity of Castaduct-42, AlMg4Fe2 (A) compared to Silafont-38, AlSi9MnMgZn (B)

Temperature [°C]

B

Ther

mal

Con

duct

ivity

[W

/(m

× K

)]

0 50 100 150 200 250 300 350 400 450 500

200

190

180

170

160

150

140

130

120

110

100

Castaduct-42 (A)

Casting alloy IC max. depth [µm] Salt spray max. raid [µm]

Surface End wall Depth Diameter

Castaduct-42 135 90 15 200

Castasil-37 235 205 150 2400

31


Dimensional stability

For proof of the excellent dimensional stability of Castaduct-42

after heating, a dilatometer curve was prepared (Fig. 8). For this

purpose two die-casted sample plates were tested. The expan-

sion was 0.44 % for 20 °C to 200 °C and corresponds to a ther-

mal expansion coefficient of 24.7 1/(K × 10-6).

The alloy Castaduct-42, unlike classic AlSiMg alloys, has no

hysteresis when heated up to 300 °C.

The lack of silicon content proves to be another advantage of

Castaduct-42: There is no detectable dimensional change after

heat input. A possible component distortion after exposure to

heat is thus prevented in the best possible way.

Application of Castaduct-42 in HPDC

Generally, the Si-free die-casting alloy Castaduct-42 can be

processed in established die-casting cells, with set up for the

production of e.g. structural parts.

Due to its chemical composition, Castaduct-42 has noticeably

lower latent heat and a somewhat higher coefficient of thermal

expansion in comparison to conventional AlSi casting alloys and

is thus closer to the values of magnesium die-casting alloys.

Shrinkage behavior

Also, the shrinkage behavior is comparable to magnesium die-

casting alloys and thus more pronounced than with AlSi casting

alloys. This has the consequence that the melt which is shot into

the mold cavity discharges the latent heat in a shorter time to

the die-casting mold contour, thus solidifying in a shorter time

interval and due to the higher shrinkage factor from the liquid

to the solid state of aggregation. Thus tends to jamming effects

on the shape of die-casting mold inserts.

The tendency to jam on die-casting mold inserts is not to be

confused or even equate set with the sticking tendency of a cast-

ing alloy with lower Fe contents and is controllable in the casting

process with suitable measures in a simple manner.

The shrinkage behavior of Si-free or Si-poor AlMg die-casting

alloys can lead to increased micro porosity, means formation of

micro shrink holes due to shrinkage deficits, and also lead to

sinkholes in the area of material amassing. Sink holes occur in

particular where hot spots occur in a die-casting mold together

with material amassing.

The shrinkage of Castaduct-42 casts is slightly larger than for

AlSi alloys and is about 0.5 % to 0.9 %.

The solidification interval with 635 °C liquidus and 580 °C

solidus temperature is on average 20 to 30 °C higher than with

AlSi die-casting alloys.

Design of casts

For Castaduct-42 casts, therefore, the special properties of this

innovative casting alloy must be considered both in the design of

the casts and mold design and in the design of the mold HPDC

process. More detailed information can be found in the chapter

Design guidelines for casts and die-casting molds.

Fig. 8: Dilatometer curve of Castaduct-42, AlMg4Fe2 after two heatings

Temperature [°C]

Ther

mic

al e

xpan

sion

[%

]

0 50 100 150 200 250 300

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

32


Melt process

The Castaduct-42 is an AlMg-type alloy with high Fe content

and must not be contaminated with Si or Mn. A microstructural

modification as required with AlSi structural casting alloys is

not required. The tendency to oxidation on the surface of the

melt bath is considerably reduced by a low content of oxidation-

inhibiting alloying ingredients. Agglomerations of oxides on bath

surfaces and on the bottom of the furnace barely form.

After rapid melting of the ingots a melt cleaning with a gas rotor

have to be carried out. The properties of Castaduct-42 are re-

tained if no sodium-containing treatment fluxes, no grain refining

or modification, no phosphorus, alkali and earth alkali containing

substances and no different metals are supplied to the melt.

The temperature during melting should not permanently exceed

780 °C. The holding temperature after melting should be set

to 760 °C (Fig. 9).

In melting furnaces, which keep the melt moving with heat con-

vection, the form of lids are reduced by less oxide-melt reactions

and segregations. This also applies to furnaces in which the bath

movement takes place by means of rotor or purge gas initiation

by furnace bottom stones.

Furnaces with roof heating and no bath movement cause difficul-

ties for longer holding time without additional refilling due to the

production with AlMg alloys.

Melting of all aluminum alloys and also Castaduct-42 reacts

less with the refractory material, if it contains more than 85 %

aluminum oxide.

The remelting of runners, return scrap and others is not a prob-

lem. However, care must be taken that mixing with other alloys

cannot take place. In particular, an increase in the silicon content

has a negative effect on the mechanical properties.

When using return material, a good melt cleaning by means of

rotor and argon or nitrogen gas is absolutely necessary, since

oxide inclusions, oxide skins, etc. have to be removed. These

can accumulate in the melting and casting process and exert a

negative influence on the component properties.

The resulting dross after cleaning and degassing cycle can

be reduced in their metal content with use of sodium-free

treatment flux.

Casting process

The quality of the cast, with regard to the mechanical charac-

teristics, the ability to deform and the weldability, is primarily

determined by the proportion of oxides and other impurities in

the melt and by the gases entrapped in the casts.

These may be due to the H2 content of the melt, residual air

in the die-casting mold cavity, release agent residues, casting

piston lubricants and residuals of moisture.

Already the melt handling in the foundry can have a big influence

on the quality of the casts. A high melt temperature can lead

to increased oxidation of the melt, which on the other hand leads

to higher oxide and hydrogen levels.

Fig 9: Typical temperature losses in melt handling during casting process; here with Castaduct-42, AlMg4Fe2

740 °C

760 °C

Metal in the HPDC chamber

Holding furnaceDosing

Transport

Melt cleaningImpeller

Melting

720 °C

680 °C

720 °C

740 °C

690 °C

650 °C

730 °C

700 °C

33


The dosage of the melt can be done by conventional dosing

furnace or ladle furnace.

The Castaduct-42 casting alloy has a higher tendency to oxidize

due to its higher Mg content and forms somewhat thicker oxide

skins compared to AlSi casting alloys.

The carryover of oxide skins into the shot sleeve can be mini-

mized if the dosing launder between dosing furnace and shot

sleeve is made of a ceramic material and this is additionally

heated.

A covered and heated dosing launder gives best performances.

An optimum is the gassing of the closed and heated dosing tube

with dry nitrogen or argon.

When using a ladle furnace, the dosing ladle must be ceramic

and ideally can be preheated directly above the melt pool surface

at high temperature. The oxide flags forming inside the ladle

during the dosing process must be removed in a suitable manner

before the renewed dosing process e.g. pour or blow out.

The dosing into the heated shot sleeve must take place as turbu-

lent free as possible in order to avoid renewed oxide formations,

combined with the increase in H2 contents, optimally. I.e. low drop

heights or not too steep dosing launder draft angles must be

taken into account.

To minimize pre-solidification of the melt within the shot sleeve,

it must be heated right through to temperatures of above 250 °C.

Ideally, this is done by a temperature control with thermal oil or an

electric heater.

It is recommended to maintain a filling ratio in the casting

chamber of about 50 %. The lower the filling ratio, the greater the

temperature drop of the melt in the shot sleeve and the greater

the proportion of pre-solidification.

After dosing, the settling time of the melt within the shot sleeve

should be kept as short as possible. Ideal are times less than

2 seconds.

Experience with the processing of Castaduct-42 showed that it

is possible to go without the biscuit cooling in the front end of

the shot sleeve, which is designed often as a water jacket. The

cooling of the biscuit takes place sufficiently quickly via the cast-

ing piston cooling and the impact plate or the protrude anvil, both

with integrated cooling, both located at the movable mold half.

This promotes the minimization of pre-solidification within the

shot sleeve which is important for best cast quality.

The die-casting mold inserts of the mold have to be preheated to

temperatures of preferably above 180 °C, measured on the die-

casting mold surface. With the steady casting process, a surface

temperature of about 200 to 240 °C should be set, e.g. also be

able for realization of long flow paths within the die-casting mold

cavity.

For vacuum-supported structural casts, the use of double-sealed

casting plungers, so-called vacuum casting plungers, is recom-

mended. These ensure that when opening the vacuum valves less

of secondary air is drawn through the melt by air gaps between

the casting piston and the shot sleeve, which could take part of

rapidly solidified melt surface, and laden with oxides, into the run-

ner or even in the die-casting mold cavity.

If a water-based mold release agent is used, it is recommended

that it should be applied with 30 % to 50 % more concentrated

than is usual with AlSi casting alloys.

This serves to better demolding of Castaduct-42 from the die-

casting mold contour, because Castaduct-42 tend to jamming.

Mold release agents developed for the processing of AlMg alloys

improve the flowability, the sliding on ejection and the weldability

of the die-cast.

It is highly recommended to apply a release agent using a min-

imum-quantity spray process, i.e. water or oil based Microspray

application. This will be avoid the use of large amounts of water,

which would lead to a high temperature drop at the die-casting

mold surface from casting cycle to casting cycle.

Furthermore, the visual quality of the cast surface and the quality

of the cast in general significantly improves and the wear and

tear of the die-casting mold inserts is positively influenced.

Due to the jamming tendency of Castaduct-42 during solidifica-

tion in the die-casting mold cavity, based on the higher shrinkage

factor in conjunction with the faster heat dissipation, the solidified

cast must be demolded quickly from the die-casting mold inserts.

The practice with Castaduct-42 shows that the shortening of

the cycle times, in particular the significant shortening of the

solidification time in the 3rd phase, leads to a better ejecting of

the casts out of the die-casting mold. Thus, in general, the jam-

ming tendency of AlMg die-casting alloys can be counteracted in

a simple manner.

At the same time a possible deformation of the cast is counter-

acted during demolding.

By shortening the total cycle time, the temperature at the die-

casting mold contour is maintained at the desired high level.

34


HPDC start and die-casting cycle

Due to the jamming tendency also the initial casts must be com-

pletely poured on the die-casting machine.

Casting at too low shot speed will not ensure the integrity of the

cast and a safely demold of the cast is not possible. The ejector

pins may pierce through the unfinished cast.

It is recommended to pour the initial casts with at least 70 % of

the plunger speed selected for the series process. Furthermore, it

is necessary to avoid any termination of the started 2nd phase in

the course of the HPDC cycle.

As part of testing the Castaduct-42 in existing AlSi die-casting

molds, the solidification times could be reduced down to the

single-digit seconds range!

The total cycle times in the die-casting process could be reduced

by one- or two-digit seconds using the Castaduct-42 die-casting

alloy!

Trimming process

The Castaduct-42 casts can be cooled directly from the casting

heat in a water bath or in air. The type of cooling has no notice-

able influence on the material properties of the finished cast.

For ductile die-casting alloys it is recommended to use a cutting

blade designed with a sloping surface, so that the ingate section,

runners, burrs, overflows and venting channels are cut off with

less force. Flat-faced punching blades squeeze with greater ef-

fort from the ingate section, with the risk of break-outs may exist.

When using cutting blades that are sloped with an angle of

approx. 3° to 5°, the required stroke for the deburring cut only

increases minimally.

The trials in the context of alloy development showed that after

demolding the cast from the die-casting mold, the shrinkage

of the solid is only slightly greater than with casts made of AlSi

casting alloys: The casts made with Castaduct-42 were punched

on a trimming tool without damage, even if designed for trimming

of AlSi casts.

Case Study

The sample cast was a structural casting with 910 mm length,

510 mm width and 6.5 kg part weight, with Castaduct-42 alloy

in a die-casting cell designed for AlSi10MnMg applications. The

shot weight was about 11 kg.

The wall thickness was over the flow path length of 850 mm in

the region of the ingate 3.5 mm and in the back wall 2.5 mm.

The Castaduct-42 was stored and kept warm in a conventional,

closed dosing furnace at 710 °C, later in the course of the trial

at 690 °C.

The temperature level of the die-casting mold was raised to

above 200 °C. As a result, the die-casting mold temperature was

on average 50 °C higher than that with AlSi alloys.

Significant is the reduction of the solidification time until ejection

in the context of the trial of originally 16 seconds to 10 seconds.

The biscuit cooling at the front end of the casting chamber was

switched off.

The plunger speed for the die-casting shot was set for a cavity

filling time of 49 ms, which made possible by the higher die-

casting mold temperature.

For the startup of the HPDC trial the release agent to water ratio

was increased for a more rich mixture from 1:100 for AlSi alloys

to 1:50 for AlMg alloys.

All Castaduct-42 casts were trimmed hand-hot without problems

with the standard trimming tool by use of the automatic sequence

in the die-casting cell.

A total of about 175 shots were poured, of which 130 shots

continuously without any interruptions. Overall, the casting result

was classified as very good. The mold filling capacity is pleas-

ingly good. The casts could be poured cleanly without signs of

cold flow, hot cracks or pulling marks. The die-casting mold itself

showed no adhesions or soldering in the area of the hollow cavity,

which would have led to pulling marks.

The measured mechanical properties for yield strength (Rp0.2),

tensile strength (Rm) and elongation (E) from Castaduct-42

structural in as-cast condition were better at yield strength and

elongation when compared to alloy AlSi10MnMg plus annealing

treatment to the state O.

Mechanical properties of HPDC trials with Castaduct-42, AlMg4Fe2

In critical cast areas with strongly turbulent filling, individual lower

values for the elongation at break were measured analogously to

the alloy AlSi10MnMg at annealing state O.

Rp0.2 (YTS)[ MPa ]

Rm (UTS)[ MPa ]

A (E)[ % ]

Structural cast 120 – 137 241 – 268 7.5 – 17.6

average 129 250 11.4

35

Get the spirit of RHEINFELDEN

Profile of the alloys for the die-casters

• no heat treatment needed to

reach high elongation

• good die-cast ejectability

• usable even for thinnest wall

thicknesses

• highest thermal and electri-

cal conductivity compared to

AlSi die-casting alloys due to

low disturbing impurities


• long-term stability

• high yield strength and excellent

elongation in the as-cast state

due to defined alloying elements


• thin wall design possible

• good die-cast ejectability

• long-term stability after

temper O

• high fatigue stress resistance;

highest compaired to AlSi-alloys

• excellent weldability


• high yield strength and elongation

in the as-cast state or after temper O,

compared to Al for rotors

• suitable to flanging, clinching or

self-piercing, especially in temper O


Treatment state YTS [ MPa ] UTS [ MPa ] E [ % ] Conductivity [ IACS % ]

F 85 – 100 200 – 230 6 – 9 < 43.5

O 80 – 100 170 –200 9 – 15 < 48.5

Treatment state Wall thickness [ mm ] YTS [ MPa ] UTS [ MPa ] E [ % ]

F 2 – 3 120 – 150 260 – 300 10 – 14

F 3 – 5 100 – 130 230 – 280 10 – 14


• applicable to thinnest wall

designs and complex designs

• air quenching after solutionizing

reduce distortion of the casts

• alloying elements enables

highest strength and good

crash properties

• good corrosion resistance due to

exact alloy limits

• high fatigue properties

• excellent weldability and

machinability

• suitable for self-piercing

Treatment state YTS [ MPa ] UTS [ MPa ] E [ % ] Hardness [ HBW ]

water-T6 230 – 280 300 – 350 6 – 9 90 – 115

air-T6 180 – 210 250 – 280 8 – 11 80 – 110

36



• best in class YTS and still 8 % E in as-cast state

for HPDC with 2 to 6 mm wall thickness

• low melt oxidation due to patented alloy addition

• high-tech alloy

• different alloying elements to control

• usage in the as-cast state for HPDC with

2 to 8 mm wall thickness

• low melt oxidation due to patented alloy addition

• high-tech alloy



• higher shrinkage in comparison to AlSi-alloys


• excellent weldability, suitable for flanging, clinching

and self-piercing riveting

• higher shrinkage in comparison to AlSi-alloys


• very high fatigue strength

• excellent weldability, suitable for flanging,

clinching and self-piercing riveting


F 2 – 4 160 – 220 310 – 340 11 – 22

F 4 – 6 140 – 170 250 – 320 9 – 14

Castaduct ®- 42 [ AlMg4Fe2 ]

• usage in the as-cast state especially for large

and thin wall HPDC

• low melt oxidation due to special alloy addition

• smart alloy composition with an AlFe eutectic

• easy handling

• no sticking to the mold due to high Fe content

• higher shrinkage due Si is < 0.20 %

• highest elongation even at room temperature


• long therm stability


F 2 – 4 120 – 150 240 – 280 10 – 22


F 2 –3 200 – 220 340 – 360 9 – 12

T5 2 –3 230 – 250 350 – 380 8 – 12

37

1 Reinigung

2 Einschmelzen der Masseln

3 Salzbehandlung

4 Strontiumabbrand

5 Abkrätzen

6 Temperatur nach dem Einschmelzen und im

Warmhalteofen 7 Entgasen und Reinigen

der Schmelze

8 Abkrätzen

9 Gießtemperatur ( Richtwerte )

10 Formtemperatur

11 Gießwerkzeug- und Gießkammer-Temperatur


Arbeitsfolge bei der Herstellung von Druckgussstücken aus Castasil-37 Öfen, Tiegel, Behandlungs- und Gießwerkzeuge reinigen, um Verunreinigungen mit

unerwünschten Elementen wie Cu, Zn und insbesondere Mg zu vermeiden !

Die Schmelze sollte zügig über 670 °C gebracht werden, um Seigerungen, z. B. des

Mn-haltigen Mischkristalles in der Schmelze zu vermeiden. Die Schmelzetemperatur

sollte 780 °C nicht übersteigen. Ein Abbrand von Sr beim Schmelzen und Warm-

halten ist zu erwarten – und umso stärker, je höher die Temperatur ist. Besonders

beim Einschmelzen von Kreislaufmaterial ist der Sr-Abbrand zu beachten und eine

Entgasungsbehandlung zum Entfernen von H2 und Oxiden empfohlen. Mit zuneh-

mendem Sr-Gehalt steigt die Neigung der Schmelze Wasserstoff aufzunehmen;

daher sollte dieser nicht über 350 ppm liegen.

beim Schmelzen nicht nötigüblicherweise Abbrand von 30 – 50 ppm je Schmelzung; Sr ist nur aufzulegieren,

wenn der Gehalt in der Schmelze unterhalb von 60 ppm liegt, mit AlSr5 oder AlSr10.

Bei erstmaligem Aufschmelzen in einem neuen Tiegel oder einem Tiegel, der

bisher nicht für Sr-veredelte Legierungen verwendet wurde, fällt der Sr-Gehalt stark

ab. Dabei diffundiert Strontium in den Tiegel; eine Sättigung ist nach erstem Auf-

schmelzen erreicht.

nach dem Einschmelzen erforderlich; kalte Werkzeuge führen, neben ihrem

Gefährdungspotenzial, eventuell zur Seigerung von Molybdän.

Dauertemperatur: maximal 780 °C ( Temperatur kontrollieren ! ); nicht unter 680 °C

sinken lassen und für Schmelzebewegung sorgen

• im Transporttiegel, besser im Gießofen bzw. Dosierofen; wirkungsvolle Reinigung

und schnellste Methode mit schnell laufendem Rotor zur Gaseinleitung,

7 – 10 l/min Argon oder Stickstoff, 6 – 10 min; bei der Entgasung im Transport-

tiegel ist mit einer Abkühlung von 30 – 50 °C zu rechnen

• Spüllanze mit feinporösem Kopf benötigt längere Behandlungszeiten ( Abkühlung ! )

nach dem Entgasen erforderlich; der Metallgehalt der Krätze kann durch die Zugabe

von Schmelzhilfssalzen bei oder nach Impellerbehandlung reduziert werden

680 – 720 °C abhängig von Gestalt, Fließweg und Wanddicke des Druckgussstückes,

aber auch von Fließrinnenlänge und -isolierung des Dosierofens sowie vom Einsatz

einer FüllbüchsenheizungTemperaturverluste können Vorerstarrungen verursachen und sind daher zu

vermeiden. 200 – 300 °C, je nach Gussstück und Anforderungen an die mechanischen

EigenschaftenGenerell gilt: je wärmer die Form, desto höher ist die Dehnung und niedriger die

Festigkeit, aber je wärmer die Form, desto dünnwandiger kann das Gussstück

gegossen werden, desto länger sind die realisierbaren Fließlängen in der Form.

Gießwerkzeug-Oberfläche: zwischen 250 und 350 °C

(abhängig von Gussstückgröße und -wanddicke)

Gießkammer elektrisch oder über Thermoöl temperiert > 200 °C

1 Einschmelzen der Masseln

2 Salzbehandlung 3 Magnesiumabbrand

4 Strontiumabbrand

5 Abkrätzen 6 Temperatur 7 Entgasen und Reinigen

der Schmelze

8 Abkrätzen


10 Formtemperatur 11 Aushärtung durch T5 12 Lösungsglühen

13 Abkühlen von

Lösungsglühtemperatur

14 Zwischenlagerzeit vor dem

Warmauslagern 15 Vollaushärtung T6 16 Überalterung T7

Silafont ®- 36 [ AlSi10MnMg ]

Arbeitsfolge bei der Herstellung von Druckgussstücken aus Silafont-36

möglichst rasch in leistungsfähigen Öfen, damit Magnesium-Abbrand, Gasaufnahme

und Oxidation der Schmelze gering bleiben; nachsetzen von vorgewärmten Masseln

und Kreislaufmaterial in kleinen Mengen, sonst Seigerungen und Oxideinschlüsse;

Kreislaufanteil kann bis 50 % betragen

beim Schmelzen nicht nötig

normalerweise Abbrand von 0,03 % je Schmelzung; ist nur zu kompensieren, wenn

der Magnesium-Gehalt der Schmelze außerhalb der Toleranz liegt, mit Magnesium-

Vorlegierung oder Reinmagnesium

üblicherweise Abbrand von 30 – 50 ppm je Schmelzung; Sr ist nur aufzulegieren,

wenn der Gehalt in der Schmelze unterhalb von 80 ppm liegt, mit AlSr5 oder AlSr10.

Bei erstmaligem Aufschmelzen in einem neuen Tiegel oder einem Tiegel, der

bisher nicht für Sr-veredelte Legierungen verwendet wurde, fällt der Sr-Gehalt stark

ab. Dabei diffundiert Strontium in den Tiegel, eine Sättigung ist nach erstem Auf-

schmelzen erreicht. nach dem Einschmelzen erforderlich

Dauertemperatur: nach dem Einschmelzen maximal 780 °C ( Temperatur kontrollieren ! )

• im Transporttiegel, besser im Warmhaltetiegel, -gefäß oder im Dosierofen mit

Bodensteinen; wirkungsvolle Reinigung und schnellste Methode mit schnell

laufendem Rotor zur Gaseinleitung, 7 – 10 l/min Argon oder Stickstoff, 6 – 10 min


• Stickstoff abgebende Spülgastabletten im Tauchglockenverfahren sind wenig geeignet.

nach dem Entgasen erforderlich; der Metallgehalt der Krätze kann durch die Zugabe

von Schmelzhilfssalzen bei oder nach der Impellerbehandlung reduziert werden

680 – 710 °C – abhängig von Gestalt, Fließweg und Wanddicke des Druckguss-

stückes, aber auch von Fließrinnenlänge des Dosierofens und von evtl. Kammerheizung

200 – 250 °C je nach Gussstück;


Wasserabschrecken direkt nach der Gussentnahme, möglichst hohe Temperatur

( dann auslagern wie 15/16 )

480 – 490 °C / 2 – 3 Stunden

für Sonderbauteile möglich: Absenkung bis 400 °C / 0,5 Stunden

möglichst ohne Verzögerung in Wasser ( 10 – 60 °C ); bei Abkühlung an Luft erreicht

man nur eine erheblich geringere Dehngrenze

nur wenn Richtarbeit notwendig, üblicherweise maximal 12 Stunden

155 – 170 °C / 2 – 3 Stunden

190 – 230 °C / 2 – 3 Stunden

Die angegebenen Glüh- und Auslagerungszeiten gelten ohne Aufheizdauer.

1 Einschmelzen der Masseln 2 Salzbehandlung

beim Einschmelzen

3 Magnesiumabbrand

4 Abkrätzen 5 Temperatur nach dem Einschmelzen

6 Temperatur im Warmhalteofen 7 Entgasen und Reinigen

der Schmelze

8 Abkrätzen

9 Kornfeinen 10 Veredelung


12 Gießwerkzeug- und

Gießkammer-Temperatur

13 Abschrecken der Gussstücke

14 Wärmebehandlung

15 Entspannungsglühen


Arbeitsfolge bei der Herstellung von Druckgussstücken aus Magsimal-59

möglichst zügig in leistungsfähigen Öfen, damit Mg-Abbrand, Gasaufnahme und

Oxidation der Schmelze gering bleiben; nachsetzen von vorgewärmten Masseln und

grobstückigem Kreislaufmaterial in kleinen Mengen, sonst Seigerungen möglich;

Feuerfestmassen mit hohem Tonerdeanteil oder dichte Stampfmassen verwenden;

Phosphor- und Natrium-Aufnahme vermeiden!

Übliches Schmelzhilfssalz verboten ! Es besteht die Gefahr der Na-Aufnahme.

normalerweise Abbrand von 0,1 % je Schmelzung, Korrektur unüblich; bei einem

Mg-Gehalt erheblich unter 5,0 % Zugabe von bis zu 0,5 % Reinmagnesium möglich

nach dem Einschmelzen erforderlich

Dauertemperatur: maximal 780 °C ( Temperatur kontrollieren ! )

nicht unter 650 °C sinken lassen und für Schmelzebewegung sorgen durch:

• Wärmekonvektion

• Rotor ( Impeller )

• Spülgaseinleitung am besten über Bodensteine

• Schmelze-Nachfüllung

keine tiefen Öfen mit Deckenheizung bei ruhender Schmelze verwenden !

• wirkungsvolle Reinigung und schnellste Methode mit schnell laufendem Rotor zur

Gaseinleitung, 7 – 10 l/min Argon oder Stickstoff, 6 – 10 min


• Spülgastabletten erreichen nicht die erforderliche Wirkung !

sorgfältiges Abkrätzen erforderlich

Um den Metallgehalt der Krätze zu verringern, dürfen nur ausgesprochen Na-freie

Salze verwendet werden !

verboten ! TiB 2 als Kornfeiner vergröbert das Eutektikum

verboten ! Die erreichbare Dehnung würde erheblich gesenkt werden.

690 – 730 °C, variiert je nach Gestalt, Größe und Wanddicke der Druckgussstücke


(abhängig von Gussstückgröße und -wanddicke)

Gießkammer elektrisch oder über Thermoöl temperiert > 200 °C

Sofortiges Abschrecken in Wasser senkt die Dehngrenze und steigert die Dehnung

(bis 70 °C).Normalerweise keine

nur in Sonderfällen T5 und O; T5 je nach Bedarf auslagern bis 250 °C und bis 90 min,

wobei Dehngrenze ansteigt und Dehnung abnimmt; O je nach Bedarf über 320 °C

bis 380 °C und bis 90 min, wobei Dehngrenze abnimmt und Dehnung ansteigt

Castaduct ®- 42 [ AlMg4Fe2 ]

Always fascinating pliable down to the finest detail

1 Melting down the ingots

2 Salt treatment during melting down

3 Silicon limit and pickup

4 Magnesium burnout

5 Iron solubility

6 Skimming

7 Temperature after melting down

8 Degassing and refining the melts

9 Skimming 10 Temperature in holding furnace

11 Grain refining

12 Modification of Si

13 Pouring temperature

(approx. values)

14 Die temperature and

die chamber temperature

15 Quenching casts after removal

from mold

16 Heat treatment

As quickly as possible in efficient furnaces to keep Mg melting loss, gas absorption

and oxidation of melts low; replenish preheated ingots and returns in small volumes to

avoid segregation.

Not needed when melting ingots; useful for avoiding oxidation when using small

returns. Prohibited to use usual salt! There is a risk of Sodium (Na) pickup.

Si is an impurity and should be below 0,15 % in the casting. Don’t melt after AlSi al-

loys.Normally melting loss of 0.1-0.2 %

per fusion, correction not normally needed; if the

Mg content is significantly below 4.0 %, add pure magnesium in portion of 0.4 %

.

Fe corrections are possible, while waiting 15 minutes at 720 °C

Needed after melting down

Maximum of 760 °C (check temperature!)

• Effective refining and fastest method using quick-running rotor for gas feeding,

7 – 10 l/min argon or nitrogen, 6 – 10 min

• Gas flushing lance with fine porous head, needs longer treatment times (cooling!)

• Gas flushing tablets do not achieve the necessary effect!

Careful skimming needed.

Only special Na-free salts may be used to reduce the metal content of skimmings!

Do not allow to fall below 660 °C and keep melt moving by means of:

• convection

• rotor (impeller)

• use bottom injection of N2

• melt pouring

Do not use deep furnace with cover heating if melt stays calm!

If needed with grain refiner based on TiB2 : 0.10 %

master alloy wire ,

wait 5 minutes before next casting.

Silicon content is below 0.15 % in the Castaduct-42. Modifying elements like Sr and P

are without any influence. Na content > 10 ppm should be avoided.

680 – 710 °C, varies depending on design, size and wall thickness of high pressure

die castingsDie surface temperature: between 200 and 350 °C

(depending on design, size and wall thickness of cast)

Preheat the chamber electrical or with oil > 200 °C

No variation in mechanical properties either with rapid water cooling nor with cooling

with airNormally none

Up to 350 °C no influence to the metallic structure!

44

Technical informations

This chapter is provided on how to work with our casting alloys in the melt process and how to gain optimum pouring

results. In the various steps in the die-cast process as possible grain refinement, strontium modification, quality of

melt, heat treatment for HPDC, surface coating, and joining techniques for the HPDC is hereby received.

We consider this a very important part of the manual as it isn’t just the quality of casting alloy used which is key

to successful applications, the right way of working before, during and after pouring is also of great importance.

More questions will certainly arise during your work and as new developments enter the market.

The RHEINFELDEN ALLOYS foundry specialists will happily answer these.

The mechanical properties are based on in-house measurements of our alloys and if applicable most exceed the

values stipulated in the EN 1706 European standard.

The mechanical values were measured at tensile bars, machined from HPDC. The ranges of mechanical properties

stated indicate the performance of the alloys and the amount of scatter depending on material and pouring. The re-

spective maximum value is for the designer’s information. These values can also be reached in the cast or sub-areas

with favorable casting conditions and corresponding casting technology work.

The HPDC alloys supplied by RHEINFELDEN ALLOYS have small and precisely defined analysis ranges in order to

ensure good uniformity in the casting process and other properties.

Processing datasheets

RHEINFELDEN ALLOYS provides the following processing data sheets in order to detail how

to work with the various alloys. If you use our casting alloys, please feel free to copy the

following pages and use them in your company. They contain practical instructions and

demonstrate the processes step by step.

Not all alloys are listed here, but the processing data sheet from within the corresponding

alloy family can be used. The recommendations correspond to typical foundry circumstances.

For example a crucible or tower melting furnace is considered for melting down;

the circumstances in a huge melting furnace may differ from the recommendations. Fine returns should also

not be used for primary aluminum HPDC alloys.

The volumes listed here are all percentages by weight, calculated for the charge weight. The temperatures quoted all

relate to the temperature of melt, even for casting. The heat treatment recommendations apply for the standard process

and may be varied, to minimise distortion for example.

If you have any questions relating to your specific alloy application and processing, please contact our foundry experts.

38


2 Flux treatment

3 Magnesium burnout

4 Strontium burnout

5 Skimming

6 Temperature


8 Skimming

9 Pouring temperature (approx. values )

10 Mold temperature

11 Solution heat treatment

12 Cooling with air

13 Cooling with water

14 Delay time before artificial ageing

15 Full artificial ageing T6-water

16 Full artificial ageing T6-air

Silafont ®- 38 [ AlSi9MnMgZn ] Sequence of work when producing high pressure die-casts from Silafont-38

As quickly as possible in efficient furnaces to keep magnesium melting loss, gas

absorption and oxidation of melts low; replenish preheated ingots and returns

in small volumes to avoid segregation and entrapped oxides; proportion of returns

may extend to 50 %

Not needed when melting

Normally a melting loss of 0.03 % per fusion; compensation is only required if the

magnesium content of the melts is outside tolerance, add magnesium master alloy

or pure magnesium

Usually melting loss of 30 – 50 ppm per fusion; Sr should only be added if the Sr

content of the melts is less than 80 ppm, add AlSr5 or AlSr10.

When fusing for the first time in a new crucible or in a crucible which has not yet

been used for Sr- modified alloys, the Sr content falls sharply. Strontium will diffuse

into the crucible, saturation is reached after the first fusion


After melting down maximum of 780 °C for holding temperature

• In the transport crucible, better in a holding crucible or receptacle or in a dosing

furnace with bottom blocks; effective refining and fastest method using

quick- running rotor for gas feeding, 7 – 10 l/min argon or nitrogen, 6 – 10 min

• Gas flushing lance with fine porous head, needs longer treatment times ( cooling ! )

• Gas flushing tablets emitting nitrogen in the bell plunger procedure are not very

suitable

Required after melting down; the metal content of the skimmings may be reduced

by adding melt fluxes within or after the impeller treatment

680 – 710 °C – depends on design, flow path and wall thickness of high pressure

die-cast, but also on the length of the flow channel in the dosing furnace and pos-

sibly on chamber heating

Mold surface temperature 250 – 350 °C

470 – 490 °C / 2 – 3 hours; for special components: 420 °C / 0.5 hours

Immediate air cooling with a cooling rate of > 3 °C / s is only achieved with an inten-

sive air stream (down to 200 °C) and results in lower distortion. If cooling in the air,

only a significantly lower yield tensile strength can be obtained

In water ( 10 – 60 °C ) without a delay wherever possible

Only if straightening is needed, usually maximum of 12 hours

155 – 190 °C / 1 – 3 hours

155 – 210 °C / 1 – 3 hours

The annealing and ageing times stated apply without a heating-up time

39

1 Refining


3 Flux treatment

4 Strontium burnout

5 Skimming



8 Skimming

9 Pouring temperature ( approx. values )

10 Mold temperature

11 Casting chamber temperature

Castasil ®- 37 [ AlSi9MnMoZr ]Sequence of work when producing high pressure die-casts from Castasil-37

Clean furnace, crucible, treatment and casting tools to avoid impurities from

unwanted elements such as Cu, Zn and especially Mg !

The melt should be quickly heated to above 670 °C to avoid segregations, e. g. of the

solid solution containing Mn in the melt. The temperature of melt should not exceed

780 °C. An Sr melting loss should be expected when melting and keeping warm –

the higher the temperature, the greater the loss. Sr melting loss should be expected

in particular when melting down returns and degassing treatment is recommended to

remove the H2 and oxides. As the Sr content increases, so does the tendency for the

melt to absorb hydrogen; this should not therefore exceed 350 ppm.





been used for Sr-modified alloys, the Sr content falls sharply. Strontium will diffuse

into the crucible; saturation is reached after the first fusion

Needed after melting down; as well as their potential for danger, cold tools may

result in molybdenum segregation

After melting down maximum of 780 °C for holding temperature. Don’t keep the melt

at temperature below 680 °C and steer melt if possible

• In the transport crucible, better in casting or dosing furnace; effective refining and

fastest method using quick-running rotor for gas feeding, 7 – 10 l/min argon or ni-

trogen, 6 – 10 min; during degassing in the transport crucible, cooling of 30 – 50 °C

should be expected


• Tablets for melt cleaning are inefficient

Required after degassing; the metal content of the skimmings may be reduced by

adding melt fluxes during or after impeller treatment

680 – 720 °C depends on design, flow path and wall thickness of high pressure

die-cast, but also on the length and insulation of the flow channel from the dosing

furnace and on use of shot sleeve heating.

Temperature losses may cause initial solidification and should therefore be avoided

250 – 350 °C, depending on cast and requirements of mechanical properties

As a rule: the warmer the mold, the higher the elongation and the lower the strength.


40

Castasil ®- 21 [ AlSi9SrE ]Sequence of work when producing high pressure die-casts from Castasil-21

1 Refining


3 Flux treatment

4 Strontium burnout

5 Skimming



8 Skimming


10 Mold and chamber temperature

11 Annealing to high conductivity

in temper O

Clean furnace, crucible, treatment and casting tools to avoid impurities from

unwanted elements such as Cu, Mg, V, Cr and especially Mn an Ti!

The melt should be quickly heated to above 670 °C to avoid segregations, e. g. of the

solid solution containing Mn in the melt. The temperature of melt should not exceed

780 °C. An Sr melting loss should be expected when melting and keeping warm –

the higher the temperature, the greater the loss. Sr melting loss should be expected

in particular when melting down returns and degassing treatment is recommended to

remove the H2 and oxides. As the Sr content increases, so does the tendency for the

melt to absorb hydrogen; this should not therefore exceed 350 ppm.





been used for Sr-modified alloys, the Sr content falls sharply. Strontium will diffuse

into the crucible; saturation is reached after the first fusion


After melting down maximum of 780 °C for holding temperature. Don’t keep the melt

at temperature below 680 °C and steer melt if possible

• In the transport crucible, better in casting or dosing furnace; effective refining

and fastest method using quick-running rotor for gas feeding, 7 – 10 l/min argon

or nitrogen, 6 – 10 min; during degassing in the transport crucible, cooling of

30 – 50 °C should be expected


• Tablets for melt cleaning are less efficient

Required after degassing; the metal content of the skimmings may be reduced by

adding melt fluxes during or after impeller treatment

680 – 720 °C depends on design, flow path and wall thickness of high pressure

die-cast, but also on the length and insulation of the flow channel from the dosing

furnace and on use of shot sleeve heating.

Temperature losses may cause initial solidification and should therefore be avoided

250 – 350 °C, depending on cast and requirements of mechanical properties

As a rule: the warmer the mold, the thinner the fins may be designed.


250 – 350 °C for 2 – 3 hours; for special purpose 440 °C for 6 hours

The annealing and ageing times stated apply without a heating-up time

41


2 Flux treatment

3 Magnesium burnout

4 Skimming


6 Temperature in holding furnace


8 Skimming

9 Grain refining

10 Modification


12 Mold temperature and

casting chamber temperature


from mold

14 Heat treatment

15 stress-relief annealing

Magsimal ®- 59 [ AlMg5Si2Mn ]Sequence of work when producing high pressure die-casts from Magsimal-59



avoid segregation; use refractory materials with a high clay content; avoid phospho-

rous and sodium absorption

Prohibited to use usual flux ! There is a risk of sodium (Na) pick up

Normally melting loss of 0.1 % per fusion, correction not normally needed; if the Mg

content is significantly below 5.0 %, add pure magnesium of maximum 0.5 %


Maximum of 780 °C ( check temperature ! )

Holding furnance temerature: 700 – 720 °C


• convection

• rotor ( impeller )


• melt pouring

Do not use deep furnace with cover heating if melt is calm !




• Gas flushing tablets do not achieve the necessary effect !

Careful skimming needed!

Only totally Na-free fluxes may be used to reduce the metal content of skimmings!

Prohibited !

Prohibited ! The elongation achievable would be reduced considerably


die-casts

Mold surface temperature 250 °C to 350 °C, depending on cast and requirements of

mechanical properties



Immediate quenching in water reduces the yield tensile strength and

increases elongation

Normally none

Only in special cases for T5 and O; if necessary, age T5 at up to 250 °C and

for up to 90 min, the yield tensile strength will increase and elongation decrease;

if necessary, age O at between 320 °C and 380 °C and for up to 90 min,

the yield tensile strength will decrease and elongation increase

42


2 Flux treatment

3 Magnesium burnout

4 Skimming




8 Skimming

9 Grain refining

10 Modification with Na or Sr

11 Pouring temperature (approx. values)




from mold

14 Heat treatment with solutionising

15 Rapid annealing with T5

16 Stress-relief annealing like temper O



avoid segregation

Prohibited to use usual flux! There is a risk of sodium (Na) pick up

Normally melting loss of 0.1–0.2 % per fusion, correction not normally needed; if the

Mg content is significantly below 6.0 %, add pure magnesium of maximum 0.5 %



Holding furnance temerature: 700 – 720 °C


• convection


• use bottom injection of Nitrogen-gas (N2)

• melt pouring

Do not use deep furnace with cover heating, if melt stays calm!






Only totally Na-free fluxes may be used to reduce the metal content

Prohibited!

Prohibited! The elongation achievable would be reduced considerably

690 – 730 °C, varies depending on design, size and wall thickness of HPDC

Mold surface temperature 250 °C to 350 °C, depending on cast design and require-

ments of mechanical properties



Immediate quenching in water reduces the yield tensile strength and increases elon-

gation. Stabile mechanical propeties are achieved after 20 days

Normally none

If necessary, age T5 at 170 °C up to 250 °C and for 30 up to 90 min, the yield tensile

strength will increase and elongation decrease slightly

If necessary, age at temperature between 320 – 380 °C and for up to 90 min, the yield

tensile strength will decrease and elongation increase

Magsimal ®- plus [ AlMg6Si2MnZr ]Sequence of work when producing high pressure die-casts from Magsimal-plus

43

Castaduct ®- 42 [ AlMg4Fe2 ]Sequence of work when producing high pressure die-casts from Castaduct - 42


2 Flux treatment during melting down

3 Silicon limit and pickup

4 Magnesium burnout

5 Iron content

6 Skimming



9 Skimming


11 Grain refining

12 Modification of Si

13 Pouring temperature

(approx. values)




from mold

16 Heat treatment



avoid segregation.

Not needed when melting ingots; useful for avoiding oxidation when using small

returns. Prohibited to use usual flux! There is a risk of sodium (Na) pickup.

Si is an impurity and should be below 0.2 % in the cast. Don’t melt after AlSi alloys.

Normally melting loss of 0.1– 0.2 % per fusion, correction normally not needed; if the

Mg content is significantly below 4.0 %, add pure magnesium in portion of 0.4 %.

Normally no correction of Fe is needed








Only special Na-free fluxes may be used to reduce the metal content of skimmings!


• convection



• melt pouring

Do not use deep furnace with cover heating if melt stays calm!

Not needed for thin-walled die-casts

Silicon content is below 0.15 % in the Castaduct-42. Modifying elements like Sr and P

are without any influence. Na content > 10 ppm should be avoided.


die-casts

Mold surface temperature: between 200 and 350 °C

(depending on design, size and wall thickness of cast)


No variation in mechanical properties either with rapid water cooling nor with cooling

with air

Normally none

Up to 350 °C no influence to the metallic structure!

44

C

D D

A

B

C

A

B

B

B

C


Design of structural die-casts

Die-casted structural components are typically large stability-

giving components, in which high component reliability is required

and which should withstand high deformations in the event of

crash of vehicles. This structural casts has to meet demands for

high strength and elongation with fewest errors as possible in the

cast structure. A structural cast is connected in individual areas

with other components by welding, gluing, riveting or crimping.

The material-side fulfillment of high strength requirements, as

possible without heat treatment to be applied, improves the

dimensional accuracy of structural casts. The additional demand

for lightweight construction is also met by thin-walled design and

high functional integration.

Important for the production of structural casts is a castable

component design with reliable processing technology of the

HPDC alloys presented in this manual. Some hints for the design

of the casts as well as the die-casting molds are given here. We

recommend that you follow these design suggestions, especially

when using our Magsimal-59 / -plus and Castaduct-42 alloys.

On the machine side, thin-walled structural casts with wall thick-

nesses of around 2.0 mm can be realized with flow path length

of approximately 1.0 m. However, it is important to ensure that

the wall thickness from casting ingate section to the end of mold

filling is performed from thick to thin, so for example from 3.5 mm

to 2.0 mm.

In the case of the more strong shrinking AlMg casting alloys, the

draft angles should be performed on contours and cores prefer-

ably minimum 1.5 °. Cast contours that tend to shrink more strong,

as well as deep, slender fin contours must be supported with

sufficient amount of ejectors for demolding from the die-casting

mold. Examples are expressed in Fig. 1.

The diameter of the ejector pins should not be less than 6.0 mm,

since AlMg casting alloys are expected to have significantly high-

er demolding forces compared to AlSi casting alloys. Also, the

risk of buckling of the ejector pins can be avoided in a practicable

way. In practice, the demolding forces are about one-third higher

and may be even higher depending on the cast design. Additional

ejector pins also significantly reduce the surface pressure on the

hot cast and with this the possible distortion of the cast.

Fig. 2: An example of good fin design

A: Fin node reducing massive concentration

B: High incoming forces are spreaded by several fins

C: Thicker diameter of ejector pins to reduce pressure force


A: Thin fin with lowered height in the middle of the length, also to reduce thickness at the fin ground

B: Adjusted core depth in small core areas

C: Ejector pin location in a tilted wall

D: Additional core pins in the area of narrow high fins


45

C

A B

The demolding of long cores should preferably be done via sleeve

ejectors. Where this cannot be done, hydraulically operated un-

derfloor core pullers can be a viable solution.

When designing fins in a cast, nodes with undesirable accumu-

lations of material should be avoided wherever possible.

In particular, high fins with large amount of taper at the flanks

cause significant volume in the bottom of the fins. The volume

contraction in such accumulations of material then causes

externally visible sink marks at the floor bottom. Remedy can

be here design provided beadings on the floor bottom side.

Deformations or even demolitions of large, core-shrinking

accumulations of material, such as assembly domes in the re-

gions of thin-walled cast contours, must be avoided. Important

for such assembly domes is a generous connection to the

thin-walled cast contours with the help of larger fin structures

(Fig. 3).

Advantageous for large-area fin designs with good component

rigidity and improved NVH characteristics are honeycomb-like fin

structures. As a result, unfavorably designed and narrow tapered

die-casting mold contours are avoided for the steel mold in a

simple manner. The honeycomb structure with its hexagon design

typically leads to 120 ° angles in the steel mold and thus reduces

hot spots with the risk of hot work steel tempering temperatures

above 550 °C during cavity filling (Fig. 4).

Small radii or even sharp edges should be avoided in die-cast

design, especially when using AlMg casting alloys. Design

specifications similar to Mg die-cast should be used. Small radii

lead to hot cracks during solidification of the metal in the die-

casting mold cavity, if there are long, freely shrinking solidification

paths is present next to it.

Heat sinks and hot cracks in the area of inner radii can be

defused by small additional fins. The skin layer formation is then

improved by the larger contact surface with the hot-working

steel (Fig. 5–7).

Other good examples of casting-oriented design are the BDG/

VDG guideline K200 as well as the BDG/VDG guideline for die-

cast made of non-ferrous metals.

Fig. 5: Solidification support through riffles; an example of solving inner edge problems through small marks


A: Design of an U-profile with thin fins, lowered in height tofollow the real stress curve in case of load (FEM calculations)

B: Separated conjunction of fins to the outer wall to avoid thicker areas

C: Hollow design on the back-side of assembly domes

Fig. 4: An example of good fin design: Honeycomb structure reduce hot spots on the mold steel


46

C

A

B

C

A

B


Design of the die-casting mold

For the production of large and thin-walled structural die-casts,

not only the casting alloy used, but also the die-casting mold

itself has to be designed to reproduce long flow paths.

Ideal for thin-walled die-casts with Castaduct-42, Magsimal-59

or Magsimal-plus is the close-to-contour design of the cool-

ing and tempering inside the mold inserts. For the die-casting

process, a temperature control of the mold inserts to over 200 °C

is recommended.

An adjustment of the thermal balance of the die-casting mold by

spraying the die-casting mold contour with the help of water

in combination with release agents should be avoided as far

as possible. This is because stress cracks on the steel occur

early when the temperature difference is particularly high.

It is recommended to carry out the release agent application

using a minimum-quantity spraying process. In this case, water,

powder or oil-based release agents can be used. Modern

simulation programs are of great help in the design of the

thermal balance of a die-casting mold.

An intensive cooling of the mold inserts in the area of the cast

runner allows rapid removal of the cast from the die-casting

mold. Although a flat and wide developed cast runner increases

the pressure surface within the die-casting mold and thus the

necessary locking force, but it leads to significantly reduced so-

lidification times. Thus, the casts can be demold in a faster way.

Furthermore, large, flat cast runners can be divided more easily

with less effort during the deburring cut. An advantage when

it comes to the handling of return scraps.

The runner as well as the ingate section has to be designed for

low turbulence and fluid flow favorable run, so without small radii

and without sharp-edged transitions. Because these increase

the flow resistance significantly and it is a greater casting force

needed for the cavity filling. Cavitation effects lead to local

vacuum zones with cross-sectional constrictions in flow-cross

sections and can suck in air via the die-casting mold parting lines

and with this into the melt.

The runner ingate section has to be placed into areas of the cast,

where the incoming melt do not immediately encounters a trans-

verse and rise barrier inside of the cavity within the flow direction.

This leads, regardless of the casting alloy used, to very strong

friction of the melt on the die-casting mold contour, so very

quickly to local heat up, and as a result, to sticking and strong

erosion. Even a significant loss of flow energy is expected.

Fig. 6: HPDC design to ensure forced solidification in the cast

A: Thinnered wall with small waffle pattern design to enlarge contact area

B: Separated fin connections

C: Outer contour casted with core to cast a wall with uniform thickness

Fig. 7: Good HPDC design to ensure forced solidification in the cast

A: Thin wall with narrow small waffle pattern design to enlarge intensively the contact surface

B: Assembly domes with hollow casted center

C: Solving inner edge problems through small marks


47

The ingate cross-section has to be generously dimensioned so

that the ingate speed of the melt remains between about 30 to

60 m/s and nevertheless a short cavity filling time is achieved. A

short cavity filling time is necessary to reduce casting defects in

thin-walled structural die-casts.

For the significant improvement of the flow properties in a die-

casting mold cavity with Castaduct-42 or Magsimal-59 / Mag-

simal-plus alloys a slightly roughened surface structure on the

die-casting mold contour is suitable. For this purpose, the local

application of tungsten carbide layers as well as for large-scale

application eroded, blasted or etched surfaces are suitable.

Also, waffle patterns are useful for improving flow properties in

thin walled areas of casts, whereby the wall thickness between

the small fins may decrease down to 1.2 mm (Fig. 6 and 7).

The die-casting mold for structural casts must be designed for a

vacuum-assisted casting process. In this case, the correctly sized

venting cross section is of great importance. It determines the

achievable flow path length of the liquid metal within the cavity

and the residual porosity in the cast (Fig. 8).

An as closed as possible melt front with only few dividing and re-

joining melt front areas leads to less oxide formation during cavity

filling and thus experience shows to significantly better casting

results, than a chaotic and highly turbulent filled cavity. Converg-

ing and thus oxide-affected melt fronts must be able to run into

overflows and ventilation channels in a defined manner.

Far-off ingate lying material accumulations, which cannot be feed

via the thin-walled structures of the cast during solidification,

must preferably be rapidly cooled. This can also be realized with

highly dissipating die-casting mold contours made of wear-

resistant tungsten steel parts inserts. Also specially designed

core pins with internal cooling channels lead to a good heat

dissipation.

Parts of die-casting mold inserts with almost any designed inte-

rior cooling can also be produced using the 3D forming process

SLM. Here, however, the recommendation is to dimension the

cooling channel cross-sections sufficiently large so that they do

not block in the casting operation by deposits.

Nevertheless, upcoming shrinkage deficits in the area of material

accumulations, which are far-off the ingate section, can be feed

by using hydraulically actuated squeezers which are common in

practice.

The die-casting mold inserts in the mold frame must be rigidly

supported so that elastic movements are avoided in the best

way possible during the HPDC process. If this is not taken

into account, the movement of a mold insert can increase the

jamming effect of the solidifying casting alloy and significantly

hinder demolding from the mold. With unfavorable die-casting

mold construction this can lead to the jamming of the cast on the

sprue side of the mold, where no ejector pins for demolding are

available.


Fig. 8: Image of a simulation to reduce entrapped air in the mold due better venting

48


Eight Target levels for HPDC

Fig. 9 shows eight levels of the HPDC process, which finally are necessary result in a cast suitable

for welding and heat treatment.

It may be more comfortable to choose an proper alloy then to handle the different HPDC processes.

Therefor also some HPDC alloys described in formers handbooks are named here.

There are higher requirements for the process of structural casts than for general purposes.

Depending on your requested targets shows the eight-level-staircase for the main areas of HPDC

some suggestions. We divide between dosing technique, air reduction in the cavity, melt handling

and application of mold release agent.

A requested high cast quality requires on the one hand the use of high-quality die-cast aluminum

alloys, also with a metallurgically proper handling of the returns. On the other hand is the consistent

application necessary by die-cast fundamentals for technical cast design, such as ingate design.

Suitable high pressure die-casting alloys

Fig. 9: Eight target levels of high pressure die-cast with details of the alloys to use and the HPDC method and stages required

AlSi10Mg ( Fe )

Silafont-36 with T5 Mg > 0.3 %

Silafont-38 T5

Magsimal-59

Magsimal-plus

Dimension

Light and thin

High yield tensile strength

Flanging

Glueing, riveting

Can be subject to high dynamic loads

Welding

Castaduct-42

AlSi9Cu3 ( Fe )

and others

Magsimal-plus

Castaduct-42

AlSi12 ( Fe )

and others

Silafont-09

Silafont-36 with Mg < 0.20 %

Castasil-37

Magsimal-59

Castaduct-42

Silafont-09

Silafont-36 T7

Castasil-37

Magsimal-59

Castaduct-42

Silafont-36

Silafont-38

Castasil-37

Magsimal-59

Magsimal-plus

Castaduct-42

Silafont-36

Silafont-38

Castasil-37

Castasil-21

Magsimal-59

Magsimal-plus

Castaduct-42

Silafont-36 T6

Silafont-36 T7

Silafont-38 T6

Micro spray application Minimisation of mold release agent Modern mold release agent

Mo

ld r

ele

ase

a

ge

nt

Target levels for HPDC

Controlled transport of melt 1st phase with less turbulence Refining treatment of melt

Me

ltA

ir

Vacuum supported Closed holding furnace Crucible, electrical heated Isolation of liner and ladle

Do

sin

gte

chn

iqu

e

HPDC method and stages needed Vacuum application Active enforced venting, vacuum supported Passive enforced venting / Chill vents Effective use of overflows (simulation)

Solution heat treatment


49

Surface coating techniques for die-casts

Maximum surface condition requirements are defined for pres-

sure die-casts which are to be coated or anodized. This applies

specifically to top-quality coatings which must meet maximum

requirements, with regard to decorative appearance and resistance

to corrosion for example in the automotive or aviation industry.

The following parameters have considerable influence on

flawless coating or anodizing:

• Pressure die-cast design and process

• Mold design and metal flow

• Handling and machining

Here some design and processing tips are reported to help

preventing detrimental influences on the coating/anodizing.

Influence from the cast design

The cast design should have no sharp edges and small radii

below 2 mm. “Thinning-out” causes running away of the

coating film at the edges during baking with significantly lower

coating thicknesses (Fig. 10).

Undercuts and bores always present problem areas in the

frequently applied electrostatic coating technology, which can

only be covered evenly with electro-dip painting (KTL).

Influence from the mold design

At least 1 % draft angle for the AlSi-alloys and at least 1.5 % for

the AlMg-based alloys should be assumed. Hot cracks may

appear in thermally loaded areas of the cast with older molds.

These mold crack marks and other burrs must be removed as

they cause “paint thinning” on their sharp edges. Deep mold cavi-

ties without melt flow through possibility must be designed with

overflows so that no air, release agent residues or any oxide

skins are included in the cast during the mold filling, which may

cause blister formation during baking of the coating.

Influence from the HPDC process

Mold release agents, preferably water based, are used for smooth

and easy removal of casts from the mold. Some of these burn into

the cast skin. Release agents containing silicon or graphite can

thus cause considerable problems. The gate area is in some cases

additionally greased in order to prevent soldering to the mold due

to increased thermal load. The ingate should not be in the visible

area of the cast as far as possible. These lubricants also cause

adhesion losses for coatings. Therefore a very economical use of

these lubricants is recommended for casts to be coated.

Surface pre-treatment

The mechanical effect of frequently applied vibratory grinding

processes is often insufficient to reliably remove cast skins,

so that a shot blasting process is recommended.

Heat treatments at solutionizing temperatures above 450 °C,

such as T4, T6 and T7 for AlSi10MnMg, produce highly oxidized

surfaces which must be considered during surface pre-treatment.

Ceramic media, such as corundum in particular, are very suitable

shot blasting media. Glass beads or aluminum granules cause

only slight material removal. Not suitable are metals and plastics,

which cause painting adhesion losses due to the penetration of

flakes into the workpiece surface. Residual iron particles also

form nuclei for pitting corrosion.

When using coolants for machining, it must be taken into account

that they have to be completely removed immediately afterwards

by degreasing. Coolants attacking aluminum must not be used.

Material compatibility and removableness of coolants must deter-

mine their selection (Fig. 11).

Fig. 10: Two-part cast for rear swinging fork for motorbike; multi-path welded structure in stiff design; powder coated

Fig. 11: Flow meter for jet fuel; chromated before coated


50


It is necessary to clean chemically the work piece prior to shot

blasting as residues from lubricant or crack testing agents can

be hammered into the workpiece surface by the shot blasting

process.

Large quantities of the mold release agents and piston lubricants

are particularly problematic as they cause burnt oil carbon residues

on the cast. Keep this in mind especially for parts in the as-cast

state.

Alkaline pickling processes for targeted roughening of the sur-

face are not recommended for the surface treatment of AlSiMg-

pressure die-casts. The high silicon content cause dark, insoluble

residues during alkaline pickling. Subsequent acid pickling is then

unavoidable for removing this “pickling deposit”. Our AlMg alloys

don’t show such effect. To optimize the paint adhesion with the

AlSi-alloys we suggest a chromate pre-treatment.

Effect of baking temperatures

Electrostatically adhering powder particles should be sintered

together on HPDC at target temperatures of 120 to maximum

200 °C. A change occurs in the mechanical properties of

AlSi10MnMg during the coating process starting from 150 °C

after 1 hour; with Magsimal-alloys this happens only above

180 °C. Furthermore mechanical properties of Magsimal-59

and Magsimal-plus gets stable after paint bake cycle treatment

with temperature above 180 °C.

Castasil-37, Castaduct-42 and Castasil-21 shows no changes.

Joining techniques for die-casts

Adhesive bonding

Magsimal-59, Magsimal-plus, Castasil-37 and Castaduct-42 are

die-casting alloys with the requested properties for structural

application in the as-cast state. There is no dimensional correction

needed due to the missing heat treatment. That gives high

benefit to assembling with adhesive bonding. Additionally there

is no longtime influence through our alloys, due low Cu and Zn

content.

Flanging

AlSi10MnMg with a magnesium content of approx. 0.16 % can

be used particularly for flanging technology. The designer can

thus join the aluminum pressure die-casts to other materials such

as steel and plastic. This can be applied as fixing but also as

structural joining technology with appropriate construction design

(Fig. 12). The configuration of the flanging edge mostly requires

an elongation of at least 8 % on the pressure die-cast material.

Therefore high internal quality requirements are set on this area

of the cast. As consequence, in this kind of applications the de-

sign of the mold must guarantee good metal flow in the flanging

edge, what has to be kept in mind especially with Magsimal-59

and Castaduct-42.

Fig. 13a: Cross section of a self-piercing riveting trial, 5 mm rivet, 1.5 mm AlMg3 sheet metal, under Castasil-37 die-cast plate in the as-cast state (F)

Fig. 12: Vibration damper housing made of AlSi10MnMg, with structural flanging

Fig. 13b: View from below


51

Patented by RHEINFELDEN ALLOYS are the alloys Magsimal-59, Magsimal-plus, Castasil-37 and Castasil-21. Silafont-38 and

Castaduct-42 are in status patent pending.

We would like to thank all our business partners who have provided have provided casts or photographs for this publication.

Special thanks to AUDI AG for the ASF picture on the front side and RWP Simtec for a picture about casting simulation.

All the details in this publication have been checked and are provided to the best of our knowledge. But just like all technical

recommendations for applications, they are not binding, are not covered by our contractual obligations ( this also applies to copy-

rights of third parties ) and we do not assume liability for them. In particular they are not promises of characteristics and do

not exempt the user from checking the products we supply for suitability for their intended purpose. Reprints, translations and

copies, including extracts, require our express approval. New alloy developments made as technology progresses after printing

are included in later versions. Version 2 – 12/2017

High pressure die-casts made from Silafont-36, Silafont-38 and

Castasil-37 are particularly well suited to welding, with both MIG

and TIG standard methods. The S - AlSi5 or S - AlSi10 welding

addition material is preferred for welded designs with AlMgSi0.5

wrought alloys.

The AlMg-based alloys, like Magsimal-59, Magsimal-plus and

Castaduct-42 have a higher shrinkage rate and force than AlSi

HPDC alloys. Mold release agents recently developed for work

with alloy family improve both the ease of flow, i.e. ability to slide

during ejection, and therefore the suitability of the high pressure

die-casts for welding.

Design welding with casts made from Magsimal-59, Magsimal-plus

and Castaduct-42 are undertaken with the addition material

S - AlMg4.5Mn using the TIG method. Unlike the case with elon-

gation, the mechanical properties in the heat influence zone

are hardly affected. The use of S-AlSi5 in AlMg die-cast alloys

would result in a decrease in elongation, and also to cracking in

the weld.

All die-casting alloys are well suited for friction stir welding or

spot welding. Spot and laser beam welding processes must take

the special features of aluminum material into account.

Self-piercing riveting

Joints in which the cast is the lower layer in the riveting joint,

have particularly high requirements concerning the absence

of defects in the casting material. Figures 13a and 13b show the

result of a self-piercing riveting trial in our laboratory.

It should be noted that Castasil-37 can be self-piercing riveted

in the as-cast state also under these severe design conditions,

i.e. using a rivet mold with flat geometry. The Castasil-37 batch

used for this trial had a yield strenght of 114 MPa, an ultimate

tensile strength of 255 MPa and 14 % elongation. A further

improvement in deformability is achieved in temper O.

Ask for our experience in self-piercing riveting with our other

alloys for structural design demands.

Welding

All here mentioned HPDC alloys are suitable for friction stir

welding and other pressure welding methods.

The suitability of HPDC for fusion welding is highly dependent

on the processes. There is no tendency for hot tearing with these

die-cast alloys. Alloys, melting and die-casting methods which

ensure low gas absorption and oxide impurity during HPDC are

needed.

The designer may place weld seams in zones with less loading,

but preferable they should also be close to the ingate, due cast

quality generally is there higher.


Wall thickness 4 mm

YTS[MPa]

UTS[MPa]

E[ %]

Ma-59 not welded 165 287 17

Ma-59 welded 148 246 6

52

GRU

PPE

DREI®

122

017

RHEINFELDEN ALLOYS GmbH & Co. KG A company of the ALUMINIUM RHEINFELDEN group Sales and Customer Support Friedrichstraße 80 D-79618 Rheinfelden

Tel. + 49 . 76 23 . 93-490 Fax + 49 . 76 23 . 93-546

alloys @ rheinfelden-alloys.eu www.rheinfelden-alloys.eu

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